Connecticut changes from Counties to Planning Regions

1960: Counties Abolished in Connecticut

In most states, counties are the primary governing entity below the state government. Their primary responsibilities often include recordkeeping, election administration, road construction and maintenance, parks management, and law and code enforcement. Most commonly, counties are governed by an elected board of supervisors or county commission that performs both legislative and executive functions. Many have other elected or appointed county positions (i.e., “row offices”), including assessors, auditors, attorneys, clerks, and tax collectors. They also act as convenient geographical regions to use for statistical purposes.

On October 1, 1960, Connecticut officially abolished counties as a system of independent government and administrative entities. The duties and functions of the state's eight counties were eliminated by legislation passed in 1959 and 1961. Prior to their elimination, county governments had limited functions. The 8 counties in Connecticut that most are familiar with (Fairfield, Hartford, Litchfield, Middlsex, New Haven, New London, Tolland, and Windham) have existed only as geographical regions since 1960. Lousiana has also done this with Parishes and Alaska with Boroughs.

2022: U.S. Census approves Petition

In 2022, the U.S. Census Bureau approved Connecticuts request to adopt its nine planning regions as county-equivalents (a petition started in August 2019). These nine planning regions replace Connecticut's eight counties used historically. They were designed to work with local geography and population to better serve as administrative boundaries. Growth in Connecticut had no regard for the original counties abolished in 1960, so a new method of division was required. This would enable a more meaningful geographic area for statistical analysis and decision making at the sub-state level. The 8 counties were replaced with 9 Councils of Government (COGs), also known as Planning Regions. The new Planning Regions were accepted with new names and FIPS Codes (below). The U.S. Census began publishing Core Based Statistical Areas (CBSAs) at the Planning Region summary level in July 2023 with the Office of Management and Budget (OMB) update.

Planning Region FIPS Code	Planning Region Name/Title	Short Name
09110	Capitol	CRCOG
09120	Greater Bridgeport	CTMetro
09130	Lower Connecticut River Valley	RiverCOG
09140	Naugatuck Valley	Naugatuck Valley
09150	Northeastern Connecticut	NECCOG
09160	Northwest Hills	Northwest Hills
09170	South Central Connecticut	SCRCOG
09180	Southeastern Connecticut	SECCOG
09190	Western Connecticut	Western CT

2024: Planning Regions go into effect

Connecticut's nine planning regions became effective as county-equivalents on July 1, 2024. This is a permanent change. The transition from data sources using counties to the new planning regions has been, and will continue to be, ongoing. The U.S. Census began releasing data at the new region level in 2023. The USPS updated its data products to use planning regions in July 2024. ZIP-Codes.com now provides the Planning Regions for each ZIP Code, but has prepared crosswalk files for those who continue to need the historical county assignment at the ZIP Code and ZIP+4 level. Also provided is a Town to COunty Crosswalk file.

Below are several maps prepared that can be used to see the relation of Towns, Historical Counties, Planning Regions, and even ZIP Codes.

Maps

See and Toggle boundaries for ZIP Codes, Towns, Historical Counties, and Planning Regions on this Interactive Connecticut Map.

Sources and Official Announcements

ZIP Code to County Crosswalk

The USPS reports a county for each ZIP Code. In July 2024, the USPS data products were updated to report the new Planning Region for each ZIP Code in place of the historical county. For many systems that rely on County information, this is a challenge. The old counties are no longer available from the Postal Service, only the new Planning Regions. Customers needing to connect ZIP Codes to Counties must add support for this exclusively for CT ZIP Codes.

The ZIP Code to County Crosswalk file for Connecticut shows the current active ZIP Codes in the state of CT. For each one, the City name and classification of the ZIP Code is shown. For the historical counties in CT, the primary County FIPS and County Name are provided as well as the new primary Planning Region FIPS and Name as assigned by the USPS.

Download Connecticut ZIP Code to County Crosswalk CSV File

ZIP Code	City	Classification	County FIPS	County Name	Region FIPS	Region Name
06001	Avon	General	09003	Hartford	09110	Capitol
06002	Bloomfield	General	09003	Hartford	09110	Capitol
06006	Windsor	Unique	09003	Hartford	09110	Capitol
06010	Bristol	General	09003	Hartford	09140	Naugatuck Vly
06011	Bristol	P.O. Box	09003	Hartford	09140	Naugatuck Vly
06013	Burlington	General	09003	Hartford	09110	Capitol
06016	Broad Brook	General	09003	Hartford	09110	Capitol
06018	Canaan	General	09005	Litchfield	09160	Nw Hills
06019	Canton	General	09003	Hartford	09110	Capitol
06020	Canton Center	P.O. Box	09003	Hartford	09110	Capitol
06021	Colebrook	General	09005	Litchfield	09160	Nw Hills
06022	Collinsville	P.O. Box	09003	Hartford	09110	Capitol
06023	East Berlin	General	09003	Hartford	09110	Capitol
06024	East Canaan	General	09005	Litchfield	09160	Nw Hills
06025	East Glastonbury	P.O. Box	09003	Hartford	09110	Capitol
06026	East Granby	General	09003	Hartford	09110	Capitol
06027	East Hartland	General	09003	Hartford	09160	Nw Hills
06028	East Windsor Hill	P.O. Box	09003	Hartford	09110	Capitol
06029	Ellington	General	09013	Tolland	09110	Capitol
06030	Farmington	Unique	09003	Hartford	09110	Capitol
06031	Falls Village	General	09005	Litchfield	09160	Nw Hills
06032	Farmington	General	09003	Hartford	09110	Capitol
06033	Glastonbury	General	09003	Hartford	09110	Capitol
06034	Farmington	P.O. Box	09003	Hartford	09110	Capitol
06035	Granby	General	09003	Hartford	09110	Capitol
06037	Berlin	General	09003	Hartford	09110	Capitol
06039	Lakeville	General	09005	Litchfield	09160	Nw Hills
06040	Manchester	General	09003	Hartford	09110	Capitol
06041	Manchester	Unique	09003	Hartford	09110	Capitol
06042	Manchester	General	09003	Hartford	09110	Capitol
06043	Bolton	General	09013	Tolland	09110	Capitol
06045	Manchester	P.O. Box	09003	Hartford	09110	Capitol
06050	New Britain	P.O. Box	09003	Hartford	09110	Capitol
06051	New Britain	General	09003	Hartford	09110	Capitol
06052	New Britain	General	09003	Hartford	09110	Capitol
06053	New Britain	General	09003	Hartford	09110	Capitol
06057	New Hartford	General	09005	Litchfield	09160	Nw Hills
06058	Norfolk	General	09005	Litchfield	09160	Nw Hills
06059	North Canton	P.O. Box	09005	Litchfield	09160	Nw Hills
06060	North Granby	General	09003	Hartford	09110	Capitol
06061	Pine Meadow	P.O. Box	09005	Litchfield	09160	Nw Hills
06062	Plainville	General	09003	Hartford	09110	Capitol
06063	Barkhamsted	General	09005	Litchfield	09160	Nw Hills
06064	Poquonock	P.O. Box	09003	Hartford	09110	Capitol
06065	Riverton	General	09003	Hartford	09160	Nw Hills
06066	Vernon Rockville	General	09013	Tolland	09110	Capitol
06067	Rocky Hill	General	09003	Hartford	09110	Capitol
06068	Salisbury	General	09005	Litchfield	09160	Nw Hills
06069	Sharon	General	09005	Litchfield	09160	Nw Hills
06070	Simsbury	General	09003	Hartford	09110	Capitol
06071	Somers	General	09013	Tolland	09110	Capitol
06072	Somersville	P.O. Box	09013	Tolland	09110	Capitol
06073	South Glastonbury	General	09003	Hartford	09110	Capitol
06074	South Windsor	General	09003	Hartford	09110	Capitol
06075	Stafford	P.O. Box	09013	Tolland	09110	Capitol
06076	Stafford Springs	General	09013	Tolland	09110	Capitol
06077	Staffordville	P.O. Box	09013	Tolland	09110	Capitol
06078	Suffield	General	09003	Hartford	09110	Capitol
06079	Taconic	P.O. Box	09005	Litchfield	09160	Nw Hills
06080	Suffield	Unique	09003	Hartford	09110	Capitol
06081	Tariffville	General	09003	Hartford	09110	Capitol
06082	Enfield	General	09003	Hartford	09110	Capitol
06083	Enfield	P.O. Box	09003	Hartford	09110	Capitol
06084	Tolland	General	09013	Tolland	09110	Capitol
06085	Unionville	General	09003	Hartford	09110	Capitol
06088	East Windsor	General	09003	Hartford	09110	Capitol
06089	Weatogue	General	09003	Hartford	09110	Capitol
06090	West Granby	General	09003	Hartford	09110	Capitol
06091	West Hartland	General	09003	Hartford	09160	Nw Hills
06092	West Simsbury	General	09003	Hartford	09110	Capitol
06093	West Suffield	General	09003	Hartford	09110	Capitol
06094	Winchester Center	P.O. Box	09005	Litchfield	09160	Nw Hills
06095	Windsor	General	09003	Hartford	09110	Capitol
06096	Windsor Locks	General	09003	Hartford	09110	Capitol
06098	Winsted	General	09005	Litchfield	09160	Nw Hills
06101	Hartford	General	09003	Hartford	09110	Capitol
06102	Hartford	P.O. Box	09003	Hartford	09110	Capitol
06103	Hartford	General	09003	Hartford	09110	Capitol
06104	Hartford	P.O. Box	09003	Hartford	09110	Capitol
06105	Hartford	General	09003	Hartford	09110	Capitol
06106	Hartford	General	09003	Hartford	09110	Capitol
06107	West Hartford	General	09003	Hartford	09110	Capitol
06108	East Hartford	General	09003	Hartford	09110	Capitol
06109	Wethersfield	General	09003	Hartford	09110	Capitol
06110	West Hartford	General	09003	Hartford	09110	Capitol
06111	Newington	General	09003	Hartford	09110	Capitol
06112	Hartford	General	09003	Hartford	09110	Capitol
06114	Hartford	General	09003	Hartford	09110	Capitol
06115	Hartford	P.O. Box	09003	Hartford	09110	Capitol
06117	West Hartford	General	09003	Hartford	09110	Capitol
06118	East Hartford	General	09003	Hartford	09110	Capitol
06119	West Hartford	General	09003	Hartford	09110	Capitol
06120	Hartford	General	09003	Hartford	09110	Capitol
06123	Hartford	P.O. Box	09003	Hartford	09110	Capitol
06126	Hartford	P.O. Box	09003	Hartford	09110	Capitol
06127	West Hartford	P.O. Box	09003	Hartford	09110	Capitol
06128	East Hartford	P.O. Box	09003	Hartford	09110	Capitol
06129	Wethersfield	P.O. Box	09003	Hartford	09110	Capitol
06131	Newington	P.O. Box	09003	Hartford	09110	Capitol
06132	Hartford	P.O. Box	09003	Hartford	09110	Capitol
06133	West Hartford	P.O. Box	09003	Hartford	09110	Capitol
06134	Hartford	P.O. Box	09003	Hartford	09110	Capitol
06137	West Hartford	P.O. Box	09003	Hartford	09110	Capitol
06138	East Hartford	P.O. Box	09003	Hartford	09110	Capitol
06140	Hartford	P.O. Box	09003	Hartford	09110	Capitol
06141	Hartford	P.O. Box	09003	Hartford	09110	Capitol
06142	Hartford	P.O. Box	09003	Hartford	09110	Capitol
06143	Hartford	P.O. Box	09003	Hartford	09110	Capitol
06144	Hartford	P.O. Box	09003	Hartford	09110	Capitol
06145	Hartford	P.O. Box	09003	Hartford	09110	Capitol
06146	Hartford	P.O. Box	09003	Hartford	09110	Capitol
06147	Hartford	P.O. Box	09003	Hartford	09110	Capitol
06150	Hartford	Unique	09003	Hartford	09110	Capitol
06151	Hartford	Unique	09003	Hartford	09110	Capitol
06152	Hartford	General	09003	Hartford	09110	Capitol
06153	Hartford	Unique	09003	Hartford	09110	Capitol
06154	Hartford	Unique	09003	Hartford	09110	Capitol
06155	Hartford	Unique	09003	Hartford	09110	Capitol
06156	Hartford	Unique	09003	Hartford	09110	Capitol
06160	Hartford	Unique	09003	Hartford	09110	Capitol
06161	Hartford	Unique	09003	Hartford	09110	Capitol
06167	Hartford	Unique	09003	Hartford	09110	Capitol
06176	Hartford	Unique	09003	Hartford	09110	Capitol
06180	Hartford	Unique	09003	Hartford	09110	Capitol
06183	Hartford	Unique	09003	Hartford	09110	Capitol
06199	Hartford	P.O. Box	09003	Hartford	09110	Capitol
06226	Willimantic	General	09015	Windham	09110	Capitol
06230	Abington	P.O. Box	09015	Windham	09150	Northeastern Ct
06231	Amston	General	09013	Tolland	09110	Capitol
06232	Andover	General	09013	Tolland	09110	Capitol
06233	Ballouville	P.O. Box	09015	Windham	09150	Northeastern Ct
06234	Brooklyn	General	09015	Windham	09150	Northeastern Ct
06235	Chaplin	General	09015	Windham	09110	Capitol
06237	Columbia	General	09013	Tolland	09110	Capitol
06238	Coventry	General	09013	Tolland	09110	Capitol
06239	Danielson	General	09015	Windham	09150	Northeastern Ct
06241	Dayville	General	09015	Windham	09150	Northeastern Ct
06242	Eastford	General	09015	Windham	09150	Northeastern Ct
06243	East Killingly	General	09015	Windham	09150	Northeastern Ct
06244	East Woodstock	P.O. Box	09015	Windham	09150	Northeastern Ct
06245	Fabyan	P.O. Box	09015	Windham	09150	Northeastern Ct
06246	Grosvenor Dale	P.O. Box	09015	Windham	09150	Northeastern Ct
06247	Hampton	General	09015	Windham	09150	Northeastern Ct
06248	Hebron	General	09013	Tolland	09110	Capitol
06249	Lebanon	General	09011	New London	09180	Southeastern Ct
06250	Mansfield Center	General	09013	Tolland	09110	Capitol
06251	Mansfield Depot	P.O. Box	09013	Tolland	09110	Capitol
06254	North Franklin	General	09011	New London	09180	Southeastern Ct
06255	North Grosvenordale	General	09015	Windham	09150	Northeastern Ct
06256	North Windham	General	09015	Windham	09110	Capitol
06258	Pomfret	P.O. Box	09015	Windham	09150	Northeastern Ct
06259	Pomfret Center	General	09015	Windham	09150	Northeastern Ct
06260	Putnam	General	09015	Windham	09150	Northeastern Ct
06262	Quinebaug	General	09015	Windham	09150	Northeastern Ct
06263	Rogers	P.O. Box	09015	Windham	09150	Northeastern Ct
06264	Scotland	General	09015	Windham	09150	Northeastern Ct
06265	South Willington	General	09013	Tolland	09110	Capitol
06266	South Windham	General	09015	Windham	09180	Southeastern Ct
06267	South Woodstock	P.O. Box	09015	Windham	09150	Northeastern Ct
06268	Storrs Mansfield	General	09013	Tolland	09110	Capitol
06269	Storrs Mansfield	Unique	09013	Tolland	09110	Capitol
06277	Thompson	General	09015	Windham	09150	Northeastern Ct
06278	Ashford	General	09015	Windham	09150	Northeastern Ct
06279	Willington	General	09013	Tolland	09110	Capitol
06280	Windham	General	09015	Windham	09150	Northeastern Ct
06281	Woodstock	General	09015	Windham	09150	Northeastern Ct
06282	Woodstock Valley	General	09015	Windham	09150	Northeastern Ct
06320	New London	General	09011	New London	09180	Southeastern Ct
06330	Baltic	General	09011	New London	09150	Northeastern Ct
06331	Canterbury	General	09015	Windham	09150	Northeastern Ct
06332	Central Village	P.O. Box	09015	Windham	09150	Northeastern Ct
06333	East Lyme	General	09011	New London	09130	Lower Ct River Vly
06334	Bozrah	General	09011	New London	09180	Southeastern Ct
06335	Gales Ferry	General	09011	New London	09180	Southeastern Ct
06336	Gilman	General	09011	New London	09180	Southeastern Ct
06338	Mashantucket	P.O. Box	09011	New London	09180	Southeastern Ct
06339	Ledyard	General	09011	New London	09180	Southeastern Ct
06340	Groton	General	09011	New London	09180	Southeastern Ct
06349	Groton	P.O. Box	09011	New London	09180	Southeastern Ct
06350	Hanover	P.O. Box	09011	New London	09180	Southeastern Ct
06351	Jewett City	General	09011	New London	09150	Northeastern Ct
06353	Montville	General	09011	New London	09180	Southeastern Ct
06354	Moosup	General	09015	Windham	09150	Northeastern Ct
06355	Mystic	General	09011	New London	09180	Southeastern Ct
06357	Niantic	General	09011	New London	09180	Southeastern Ct
06359	North Stonington	General	09011	New London	09180	Southeastern Ct
06360	Norwich	General	09011	New London	09180	Southeastern Ct
06365	Preston	General	09011	New London	09180	Southeastern Ct
06370	Oakdale	General	09011	New London	09180	Southeastern Ct
06371	Old Lyme	General	09011	New London	09130	Lower Ct River Vly
06372	Old Mystic	P.O. Box	09011	New London	09180	Southeastern Ct
06373	Oneco	P.O. Box	09015	Windham	09150	Northeastern Ct
06374	Plainfield	General	09015	Windham	09150	Northeastern Ct
06375	Quaker Hill	General	09011	New London	09180	Southeastern Ct
06376	South Lyme	P.O. Box	09011	New London	09130	Lower Ct River Vly
06377	Sterling	General	09015	Windham	09150	Northeastern Ct
06378	Stonington	General	09011	New London	09180	Southeastern Ct
06379	Pawcatuck	General	09011	New London	09180	Southeastern Ct
06380	Taftville	General	09011	New London	09180	Southeastern Ct
06382	Uncasville	General	09011	New London	09180	Southeastern Ct
06383	Versailles	P.O. Box	09011	New London	09180	Southeastern Ct
06384	Voluntown	General	09011	New London	09150	Northeastern Ct
06385	Waterford	General	09011	New London	09180	Southeastern Ct
06387	Wauregan	P.O. Box	09015	Windham	09150	Northeastern Ct
06388	West Mystic	P.O. Box	09011	New London	09180	Southeastern Ct
06389	Yantic	General	09011	New London	09180	Southeastern Ct
06401	Ansonia	General	09009	New Haven	09140	Naugatuck Vly
06403	Beacon Falls	General	09009	New Haven	09140	Naugatuck Vly
06404	Botsford	P.O. Box	09001	Fairfield	09190	Western Ct
06405	Branford	General	09009	New Haven	09170	South Central Ct
06408	Cheshire	Unique	09009	New Haven	09140	Naugatuck Vly
06409	Centerbrook	General	09007	Middlesex	09130	Lower Ct River Vly
06410	Cheshire	General	09009	New Haven	09110	Capitol
06411	Cheshire	Unique	09009	New Haven	09140	Naugatuck Vly
06412	Chester	General	09007	Middlesex	09130	Lower Ct River Vly
06413	Clinton	General	09007	Middlesex	09130	Lower Ct River Vly
06414	Cobalt	P.O. Box	09007	Middlesex	09130	Lower Ct River Vly
06415	Colchester	General	09011	New London	09110	Capitol
06416	Cromwell	General	09007	Middlesex	09110	Capitol
06417	Deep River	General	09007	Middlesex	09130	Lower Ct River Vly
06418	Derby	General	09009	New Haven	09140	Naugatuck Vly
06419	Killingworth	General	09007	Middlesex	09130	Lower Ct River Vly
06420	Salem	General	09011	New London	09130	Lower Ct River Vly
06422	Durham	General	09007	Middlesex	09130	Lower Ct River Vly
06423	East Haddam	General	09007	Middlesex	09130	Lower Ct River Vly
06424	East Hampton	General	09007	Middlesex	09130	Lower Ct River Vly
06426	Essex	General	09007	Middlesex	09130	Lower Ct River Vly
06437	Guilford	General	09009	New Haven	09170	South Central Ct
06438	Haddam	General	09007	Middlesex	09130	Lower Ct River Vly
06439	Hadlyme	P.O. Box	09011	New London	09180	Southeastern Ct
06440	Hawleyville	P.O. Box	09001	Fairfield	09190	Western Ct
06441	Higganum	General	09007	Middlesex	09130	Lower Ct River Vly
06442	Ivoryton	General	09007	Middlesex	09130	Lower Ct River Vly
06443	Madison	General	09009	New Haven	09170	South Central Ct
06444	Marion	P.O. Box	09003	Hartford	09110	Capitol
06447	Marlborough	General	09003	Hartford	09110	Capitol
06450	Meriden	General	09009	New Haven	09130	Lower Ct River Vly
06451	Meriden	General	09009	New Haven	09110	Capitol
06455	Middlefield	General	09007	Middlesex	09130	Lower Ct River Vly
06456	Middle Haddam	P.O. Box	09007	Middlesex	09130	Lower Ct River Vly
06457	Middletown	General	09007	Middlesex	09130	Lower Ct River Vly
06459	Middletown	Unique	09007	Middlesex	09130	Lower Ct River Vly
06460	Milford	General	09009	New Haven	09170	South Central Ct
06461	Milford	General	09009	New Haven	09170	South Central Ct
06467	Milldale	P.O. Box	09003	Hartford	09110	Capitol
06468	Monroe	General	09001	Fairfield	09120	Greater Bridgeport
06469	Moodus	General	09007	Middlesex	09130	Lower Ct River Vly
06470	Newtown	General	09001	Fairfield	09190	Western Ct
06471	North Branford	General	09009	New Haven	09170	South Central Ct
06472	Northford	General	09009	New Haven	09170	South Central Ct
06473	North Haven	General	09009	New Haven	09170	South Central Ct
06474	North Westchester	P.O. Box	09011	New London	09180	Southeastern Ct
06475	Old Saybrook	General	09007	Middlesex	09130	Lower Ct River Vly
06477	Orange	General	09009	New Haven	09140	Naugatuck Vly
06478	Oxford	General	09009	New Haven	09140	Naugatuck Vly
06479	Plantsville	General	09003	Hartford	09110	Capitol
06480	Portland	General	09007	Middlesex	09130	Lower Ct River Vly
06481	Rockfall	General	09007	Middlesex	09130	Lower Ct River Vly
06482	Sandy Hook	General	09001	Fairfield	09190	Western Ct
06483	Seymour	General	09009	New Haven	09140	Naugatuck Vly
06484	Shelton	General	09001	Fairfield	09120	Greater Bridgeport
06487	South Britain	P.O. Box	09009	New Haven	09140	Naugatuck Vly
06488	Southbury	General	09009	New Haven	09140	Naugatuck Vly
06489	Southington	General	09003	Hartford	09110	Capitol
06491	Stevenson	P.O. Box	09001	Fairfield	09120	Greater Bridgeport
06492	Wallingford	General	09009	New Haven	09140	Naugatuck Vly
06493	Wallingford	Unique	09009	New Haven	09170	South Central Ct
06494	Wallingford	Unique	09009	New Haven	09170	South Central Ct
06495	Wallingford	Unique	09009	New Haven	09170	South Central Ct
06498	Westbrook	General	09007	Middlesex	09130	Lower Ct River Vly
06501	New Haven	P.O. Box	09009	New Haven	09170	South Central Ct
06502	New Haven	P.O. Box	09009	New Haven	09170	South Central Ct
06503	New Haven	P.O. Box	09009	New Haven	09170	South Central Ct
06504	New Haven	P.O. Box	09009	New Haven	09170	South Central Ct
06505	New Haven	P.O. Box	09009	New Haven	09170	South Central Ct
06506	New Haven	P.O. Box	09009	New Haven	09170	South Central Ct
06507	New Haven	P.O. Box	09009	New Haven	09170	South Central Ct
06508	New Haven	P.O. Box	09009	New Haven	09170	South Central Ct
06509	New Haven	P.O. Box	09009	New Haven	09170	South Central Ct
06510	New Haven	General	09009	New Haven	09170	South Central Ct
06511	New Haven	General	09009	New Haven	09170	South Central Ct
06512	East Haven	General	09009	New Haven	09170	South Central Ct
06513	New Haven	General	09009	New Haven	09170	South Central Ct
06514	Hamden	General	09009	New Haven	09170	South Central Ct
06515	New Haven	General	09009	New Haven	09170	South Central Ct
06516	West Haven	General	09009	New Haven	09170	South Central Ct
06517	Hamden	General	09009	New Haven	09170	South Central Ct
06518	Hamden	General	09009	New Haven	09170	South Central Ct
06519	New Haven	General	09009	New Haven	09170	South Central Ct
06520	New Haven	P.O. Box	09009	New Haven	09170	South Central Ct
06521	New Haven	P.O. Box	09009	New Haven	09170	South Central Ct
06524	Bethany	General	09009	New Haven	09170	South Central Ct
06525	Woodbridge	General	09009	New Haven	09170	South Central Ct
06530	New Haven	P.O. Box	09009	New Haven	09170	South Central Ct
06531	New Haven	P.O. Box	09009	New Haven	09170	South Central Ct
06532	New Haven	P.O. Box	09009	New Haven	09170	South Central Ct
06533	New Haven	P.O. Box	09009	New Haven	09170	South Central Ct
06534	New Haven	P.O. Box	09009	New Haven	09170	South Central Ct
06535	New Haven	P.O. Box	09009	New Haven	09170	South Central Ct
06536	New Haven	P.O. Box	09009	New Haven	09170	South Central Ct
06537	New Haven	Unique	09009	New Haven	09170	South Central Ct
06538	New Haven	Unique	09009	New Haven	09170	South Central Ct
06540	New Haven	Unique	09009	New Haven	09170	South Central Ct
06601	Bridgeport	P.O. Box	09001	Fairfield	09120	Greater Bridgeport
06602	Bridgeport	P.O. Box	09001	Fairfield	09120	Greater Bridgeport
06604	Bridgeport	General	09001	Fairfield	09120	Greater Bridgeport
06605	Bridgeport	General	09001	Fairfield	09120	Greater Bridgeport
06606	Bridgeport	General	09001	Fairfield	09120	Greater Bridgeport
06607	Bridgeport	General	09001	Fairfield	09120	Greater Bridgeport
06608	Bridgeport	General	09001	Fairfield	09120	Greater Bridgeport
06610	Bridgeport	General	09001	Fairfield	09120	Greater Bridgeport
06611	Trumbull	General	09001	Fairfield	09120	Greater Bridgeport
06612	Easton	General	09001	Fairfield	09120	Greater Bridgeport
06614	Stratford	General	09001	Fairfield	09120	Greater Bridgeport
06615	Stratford	General	09001	Fairfield	09120	Greater Bridgeport
06673	Bridgeport	Unique	09001	Fairfield	09120	Greater Bridgeport
06699	Bridgeport	Unique	09001	Fairfield	09120	Greater Bridgeport
06701	Waterbury	General	09009	New Haven	09140	Naugatuck Vly
06702	Waterbury	General	09009	New Haven	09140	Naugatuck Vly
06703	Waterbury	P.O. Box	09009	New Haven	09140	Naugatuck Vly
06704	Waterbury	General	09009	New Haven	09140	Naugatuck Vly
06705	Waterbury	General	09009	New Haven	09140	Naugatuck Vly
06706	Waterbury	General	09009	New Haven	09140	Naugatuck Vly
06708	Waterbury	General	09009	New Haven	09140	Naugatuck Vly
06710	Waterbury	General	09009	New Haven	09140	Naugatuck Vly
06712	Prospect	General	09009	New Haven	09140	Naugatuck Vly
06716	Wolcott	General	09009	New Haven	09110	Capitol
06720	Waterbury	P.O. Box	09009	New Haven	09140	Naugatuck Vly
06721	Waterbury	P.O. Box	09009	New Haven	09140	Naugatuck Vly
06722	Waterbury	P.O. Box	09009	New Haven	09140	Naugatuck Vly
06723	Waterbury	P.O. Box	09009	New Haven	09140	Naugatuck Vly
06724	Waterbury	P.O. Box	09009	New Haven	09140	Naugatuck Vly
06725	Waterbury	P.O. Box	09009	New Haven	09140	Naugatuck Vly
06726	Waterbury	P.O. Box	09009	New Haven	09140	Naugatuck Vly
06750	Bantam	General	09005	Litchfield	09160	Nw Hills
06751	Bethlehem	General	09005	Litchfield	09140	Naugatuck Vly
06752	Bridgewater	General	09005	Litchfield	09160	Nw Hills
06753	Cornwall	P.O. Box	09005	Litchfield	09160	Nw Hills
06754	Cornwall Bridge	General	09005	Litchfield	09160	Nw Hills
06755	Gaylordsville	General	09005	Litchfield	09190	Western Ct
06756	Goshen	General	09005	Litchfield	09160	Nw Hills
06757	Kent	General	09005	Litchfield	09160	Nw Hills
06758	Lakeside	General	09005	Litchfield	09160	Nw Hills
06759	Litchfield	General	09005	Litchfield	09160	Nw Hills
06762	Middlebury	General	09009	New Haven	09140	Naugatuck Vly
06763	Morris	General	09005	Litchfield	09140	Naugatuck Vly
06770	Naugatuck	General	09009	New Haven	09140	Naugatuck Vly
06776	New Milford	General	09005	Litchfield	09160	Nw Hills
06777	New Preston Marble Dale	General	09005	Litchfield	09160	Nw Hills
06778	Northfield	General	09005	Litchfield	09140	Naugatuck Vly
06779	Oakville	General	09005	Litchfield	09140	Naugatuck Vly
06781	Pequabuck	P.O. Box	09005	Litchfield	09140	Naugatuck Vly
06782	Plymouth	General	09005	Litchfield	09140	Naugatuck Vly
06783	Roxbury	General	09005	Litchfield	09160	Nw Hills
06784	Sherman	General	09001	Fairfield	09190	Western Ct
06785	South Kent	General	09005	Litchfield	09160	Nw Hills
06786	Terryville	General	09005	Litchfield	09140	Naugatuck Vly
06787	Thomaston	General	09005	Litchfield	09140	Naugatuck Vly
06790	Torrington	General	09005	Litchfield	09160	Nw Hills
06791	Harwinton	General	09005	Litchfield	09160	Nw Hills
06792	Torrington	Unique	09005	Litchfield	09160	Nw Hills
06793	Washington	General	09005	Litchfield	09140	Naugatuck Vly
06794	Washington Depot	General	09005	Litchfield	09160	Nw Hills
06795	Watertown	General	09005	Litchfield	09140	Naugatuck Vly
06796	West Cornwall	General	09005	Litchfield	09160	Nw Hills
06798	Woodbury	General	09005	Litchfield	09140	Naugatuck Vly
06801	Bethel	General	09001	Fairfield	09190	Western Ct
06804	Brookfield	General	09001	Fairfield	09190	Western Ct
06807	Cos Cob	General	09001	Fairfield	09190	Western Ct
06810	Danbury	General	09001	Fairfield	09190	Western Ct
06811	Danbury	General	09001	Fairfield	09190	Western Ct
06812	New Fairfield	General	09001	Fairfield	09190	Western Ct
06813	Danbury	P.O. Box	09001	Fairfield	09190	Western Ct
06820	Darien	General	09001	Fairfield	09190	Western Ct
06824	Fairfield	General	09001	Fairfield	09120	Greater Bridgeport
06825	Fairfield	General	09001	Fairfield	09120	Greater Bridgeport
06828	Fairfield	General	09001	Fairfield	09120	Greater Bridgeport
06829	Georgetown	P.O. Box	09001	Fairfield	09190	Western Ct
06830	Greenwich	General	09001	Fairfield	09190	Western Ct
06831	Greenwich	General	09001	Fairfield	09190	Western Ct
06836	Greenwich	P.O. Box	09001	Fairfield	09190	Western Ct
06838	Greens Farms	P.O. Box	09001	Fairfield	09190	Western Ct
06840	New Canaan	General	09001	Fairfield	09190	Western Ct
06850	Norwalk	General	09001	Fairfield	09190	Western Ct
06851	Norwalk	General	09001	Fairfield	09190	Western Ct
06852	Norwalk	P.O. Box	09001	Fairfield	09190	Western Ct
06853	Norwalk	General	09001	Fairfield	09190	Western Ct
06854	Norwalk	General	09001	Fairfield	09190	Western Ct
06855	Norwalk	General	09001	Fairfield	09190	Western Ct
06856	Norwalk	P.O. Box	09001	Fairfield	09190	Western Ct
06857	Norwalk	Unique	09001	Fairfield	09190	Western Ct
06858	Norwalk	Unique	09001	Fairfield	09190	Western Ct
06860	Norwalk	Unique	09001	Fairfield	09190	Western Ct
06870	Old Greenwich	General	09001	Fairfield	09190	Western Ct
06875	Redding Center	P.O. Box	09001	Fairfield	09190	Western Ct
06876	Redding Ridge	P.O. Box	09001	Fairfield	09190	Western Ct
06877	Ridgefield	General	09001	Fairfield	09190	Western Ct
06878	Riverside	General	09001	Fairfield	09190	Western Ct
06879	Ridgefield	Unique	09001	Fairfield	09190	Western Ct
06880	Westport	General	09001	Fairfield	09190	Western Ct
06881	Westport	P.O. Box	09001	Fairfield	09190	Western Ct
06883	Weston	General	09001	Fairfield	09190	Western Ct
06888	Westport	Unique	09001	Fairfield	09190	Western Ct
06889	Westport	Unique	09001	Fairfield	09190	Western Ct
06890	Southport	General	09001	Fairfield	09120	Greater Bridgeport
06896	Redding	General	09001	Fairfield	09120	Greater Bridgeport
06897	Wilton	General	09001	Fairfield	09190	Western Ct
06901	Stamford	General	09001	Fairfield	09190	Western Ct
06902	Stamford	General	09001	Fairfield	09190	Western Ct
06903	Stamford	General	09001	Fairfield	09190	Western Ct
06904	Stamford	P.O. Box	09001	Fairfield	09190	Western Ct
06905	Stamford	General	09001	Fairfield	09190	Western Ct
06906	Stamford	General	09001	Fairfield	09190	Western Ct
06907	Stamford	General	09001	Fairfield	09190	Western Ct
06910	Stamford	General	09001	Fairfield	09190	Western Ct
06911	Stamford	P.O. Box	09001	Fairfield	09190	Western Ct
06912	Stamford	P.O. Box	09001	Fairfield	09190	Western Ct
06913	Stamford	Unique	09001	Fairfield	09190	Western Ct
06914	Stamford	Unique	09001	Fairfield	09190	Western Ct
06926	Stamford	Unique	09001	Fairfield	09190	Western Ct
06927	Stamford	Unique	09001	Fairfield	09190	Western Ct

Show All

ZIP Codes do cross County/Planning Region boundaries. The USPS only assigns a primary region to each ZIP Code. The crosswalk table above shows the primary County as well as the primary Planning Region for each ZIP Code.

ZIP+4 to County Crosswalk

The USPS reports a county for each ZIP+4 record. In July 2024, the USPS data products were updated to report the new Planning Region for each ZIP+4 in place of the historical county. For many systems that rely on County information, this is a challenge. The old counties are no longer available from the Postal Service, only the new Planning Regions. Customers needing to connect ZIP+4 records to Counties must add support for this exclusively for CT ZIP Codes.

The ZIP+4 to County Crosswalk file for Connecticut shows the current active ZIP+4 records in the state of CT. Each record in this file includes the USPS supplied Update Key, ZIP Code, ZIP+4 Low Number, ZIP+4 High Number, Region FIPS, Region Name, Historical County FIPS, and Historical County Name. You can marry this information to the ZIP+4 data by using either the UpdateKey or ZIP Code and ZIP+4.

Download Connecticut ZIP+4 to County Crosswalk CSV File

Update Key	ZIP Code	ZIP 4 Low	ZIP 4 High	Region FIPS	Region Name	County FIPS	County Name
V214377989	06001	0001	0120	09110	CAPITOL	09003	HARTFORD
V214377992	06001	0121	0240	09110	CAPITOL	09003	HARTFORD
V214387770	06010	5316	5316	09140	NAUGATUCK VLY	09003	HARTFORD
V214389300	06010	5317	5317	09140	NAUGATUCK VLY	09003	HARTFORD
V214390930	06018	2552	2552	09160	NW HILLS	09005	LITCHFIELD
V214390931	06018	2553	2553	09160	NW HILLS	09005	LITCHFIELD
V214394306	06029	5838	5838	09110	CAPITOL	09013	TOLLAND
V214519263	06351	1130	1130	09180	SOUTHEASTERN CT	09011	NEW LONDON
V214519262	06351	1130	1130	09180	SOUTHEASTERN CT	09011	NEW LONDON
V214871121	06437	1414	1414	09170	SOUTH CENTRAL CT	09009	NEW HAVEN
V214871115	06437	1415	1415	09170	SOUTH CENTRAL CT	09009	NEW HAVEN
V214608845	06483	2979	2979	09140	NAUGATUCK VLY	09009	NEW HAVEN
V214608308	06483	2997	2997	09140	NAUGATUCK VLY	09009	NEW HAVEN
V214694812	06615	7777	7777	09120	GREATER BRIDGEPORT	09001	FAIRFIELD
V214693277	06615	7778	7778	09120	GREATER BRIDGEPORT	09001	FAIRFIELD
V214726118	06786	4622	4622	09140	NAUGATUCK VLY	09005	LITCHFIELD
V214726414	06786	4623	4623	09140	NAUGATUCK VLY	09005	LITCHFIELD
V214754387	06820	3710	3710	09190	WESTERN CT	09001	FAIRFIELD
V214754503	06820	3711	3711	09190	WESTERN CT	09001	FAIRFIELD

This is only a sample of data from the ZIP+4 to County Crosswalk. There are over 450,000 records in this file.

Town to County Crosswalk

The U.S. Census Bureau adopted Connecticut's nine planning regions as county equivalents-- new county-level geographies for Connecticut for statistical purposes, replacing Connecticut's eight counties in Census Bureau data products. The county equivalents have new FIPS codes.

The U.S. Census Bureau data and publications have transitions to using the county equivalents instead of counties in 2023. To help ease this transition, this crosswalk includes town FIPS codes for both the original counties and the new county equivalent Planning regions. Towns therefore have two FIPS identifiers. The town boundaries did not change.

TownFIPS2020 include the FIPS code from its county.

TownFIPS2022 include the FIPS code from its county equivalent/planning region.

Download Connecticut Town to County Crosswalk CSV File

Town	TownFIPS2020	TownFIPS2022	RegionFIPS	RegionName	CountyFIPS	CountyName
Andover	0901301080	0911001080	09110	Capitol	09013	Tolland
Ansonia	0900901220	0914001220	09140	Naugatuck Valley	09009	New Haven
Ashford	0901501430	0915001430	09150	Northeastern Connecticut	09015	Windham
Avon	0900302060	0911002060	09110	Capitol	09003	Hartford
Barkhamsted	0900502760	0916002760	09160	Northwest Hills	09005	Litchfield
Beacon Falls	0900903250	0914003250	09140	Naugatuck Valley	09009	New Haven
Berlin	0900304300	0911004300	09110	Capitol	09003	Hartford
Bethany	0900904580	0917004580	09170	South Central Connecticut	09009	New Haven
Bethel	0900104720	0919004720	09190	Western Connecticut	09001	Fairfield
Bethlehem	0900504930	0914004930	09140	Naugatuck Valley	09005	Litchfield
Bloomfield	0900305910	0911005910	09110	Capitol	09003	Hartford
Bolton	0901306260	0911006260	09110	Capitol	09013	Tolland
Bozrah	0901106820	0918006820	09180	Southeastern Connecticut	09011	New London
Branford	0900907310	0917007310	09170	South Central Connecticut	09009	New Haven
Bridgeport	0900108070	0912008070	09120	Greater Bridgeport	09001	Fairfield
Bridgewater	0900508210	0919008210	09190	Western Connecticut	09005	Litchfield
Bristol	0900308490	0914008490	09140	Naugatuck Valley	09003	Hartford
Brookfield	0900108980	0919008980	09190	Western Connecticut	09001	Fairfield
Brooklyn	0901509190	0915009190	09150	Northeastern Connecticut	09015	Windham
Burlington	0900310100	0916010100	09160	Northwest Hills	09003	Hartford
Canaan	0900510940	0916010940	09160	Northwest Hills	09005	Litchfield
Canterbury	0901512130	0915012130	09150	Northeastern Connecticut	09015	Windham
Canton	0900312270	0911012270	09110	Capitol	09003	Hartford
Chaplin	0901513810	0915013810	09150	Northeastern Connecticut	09015	Windham
Cheshire	0900914160	0914014160	09140	Naugatuck Valley	09009	New Haven
Chester	0900714300	0913014300	09130	Lower Connecticut River Valley	09007	Middlesex
Clinton	0900715350	0913015350	09130	Lower Connecticut River Valley	09007	Middlesex
Colchester	0901115910	0918015910	09180	Southeastern Connecticut	09011	New London
Colebrook	0900516050	0916016050	09160	Northwest Hills	09005	Litchfield
Columbia	0901316400	0911016400	09110	Capitol	09013	Tolland
Cornwall	0900517240	0916017240	09160	Northwest Hills	09005	Litchfield
Coventry	0901317800	0911017800	09110	Capitol	09013	Tolland
Cromwell	0900718080	0913018080	09130	Lower Connecticut River Valley	09007	Middlesex
Danbury	0900118500	0919018500	09190	Western Connecticut	09001	Fairfield
Darien	0900118850	0919018850	09190	Western Connecticut	09001	Fairfield
Deep River	0900719130	0913019130	09130	Lower Connecticut River Valley	09007	Middlesex
Derby	0900919550	0914019550	09140	Naugatuck Valley	09009	New Haven
Durham	0900720810	0913020810	09130	Lower Connecticut River Valley	09007	Middlesex
East Granby	0900322070	0911022070	09110	Capitol	09003	Hartford
East Haddam	0900722280	0913022280	09130	Lower Connecticut River Valley	09007	Middlesex
East Hampton	0900722490	0913022490	09130	Lower Connecticut River Valley	09007	Middlesex
East Hartford	0900322630	0911022630	09110	Capitol	09003	Hartford
East Haven	0900922910	0917022910	09170	South Central Connecticut	09009	New Haven
East Lyme	0901123400	0918023400	09180	Southeastern Connecticut	09011	New London
East Windsor	0900324800	0911024800	09110	Capitol	09003	Hartford
Eastford	0901521860	0915021860	09150	Northeastern Connecticut	09015	Windham
Easton	0900123890	0912023890	09120	Greater Bridgeport	09001	Fairfield
Ellington	0901325360	0911025360	09110	Capitol	09013	Tolland
Enfield	0900325990	0911025990	09110	Capitol	09003	Hartford
Essex	0900726270	0913026270	09130	Lower Connecticut River Valley	09007	Middlesex
Fairfield	0900126620	0912026620	09120	Greater Bridgeport	09001	Fairfield
Farmington	0900327600	0911027600	09110	Capitol	09003	Hartford
Franklin	0901129910	0918029910	09180	Southeastern Connecticut	09011	New London
Glastonbury	0900331240	0911031240	09110	Capitol	09003	Hartford
Goshen	0900532290	0916032290	09160	Northwest Hills	09005	Litchfield
Granby	0900332640	0911032640	09110	Capitol	09003	Hartford
Greenwich	0900133620	0919033620	09190	Western Connecticut	09001	Fairfield
Griswold	0901133900	0918033900	09180	Southeastern Connecticut	09011	New London
Groton	0901134250	0918034250	09180	Southeastern Connecticut	09011	New London
Guilford	0900934950	0917034950	09170	South Central Connecticut	09009	New Haven
Haddam	0900735230	0913035230	09130	Lower Connecticut River Valley	09007	Middlesex
Hamden	0900935650	0917035650	09170	South Central Connecticut	09009	New Haven
Hampton	0901536000	0915036000	09150	Northeastern Connecticut	09015	Windham
Hartford	0900337070	0911037070	09110	Capitol	09003	Hartford
Hartland	0900337140	0916037140	09160	Northwest Hills	09003	Hartford
Harwinton	0900537280	0916037280	09160	Northwest Hills	09005	Litchfield
Hebron	0901337910	0911037910	09110	Capitol	09013	Tolland
Kent	0900540290	0916040290	09160	Northwest Hills	09005	Litchfield
Killingly	0901540500	0915040500	09150	Northeastern Connecticut	09015	Windham
Killingworth	0900740710	0913040710	09130	Lower Connecticut River Valley	09007	Middlesex
Lebanon	0901142390	0918042390	09180	Southeastern Connecticut	09011	New London
Ledyard	0901142600	0918042600	09180	Southeastern Connecticut	09011	New London
Lisbon	0901143230	0918043230	09180	Southeastern Connecticut	09011	New London
Litchfield	0900543370	0916043370	09160	Northwest Hills	09005	Litchfield
Lyme	0901144210	0913044210	09130	Lower Connecticut River Valley	09011	New London
Madison	0900944560	0917044560	09170	South Central Connecticut	09009	New Haven
Manchester	0900344700	0911044700	09110	Capitol	09003	Hartford
Mansfield	0901344910	0911044910	09110	Capitol	09013	Tolland
Marlborough	0900345820	0911045820	09110	Capitol	09003	Hartford
Meriden	0900946520	0917046520	09170	South Central Connecticut	09009	New Haven
Middlebury	0900946940	0914046940	09140	Naugatuck Valley	09009	New Haven
Middlefield	0900747080	0913047080	09130	Lower Connecticut River Valley	09007	Middlesex
Middletown	0900747360	0913047360	09130	Lower Connecticut River Valley	09007	Middlesex
Milford	0900947535	0917047535	09170	South Central Connecticut	09009	New Haven
Monroe	0900148620	0912048620	09120	Greater Bridgeport	09001	Fairfield
Montville	0901148900	0918048900	09180	Southeastern Connecticut	09011	New London
Morris	0900549460	0916049460	09160	Northwest Hills	09005	Litchfield
Naugatuck	0900949950	0914049950	09140	Naugatuck Valley	09009	New Haven
New Britain	0900350440	0911050440	09110	Capitol	09003	Hartford
New Canaan	0900150580	0919050580	09190	Western Connecticut	09001	Fairfield
New Fairfield	0900150860	0919050860	09190	Western Connecticut	09001	Fairfield
New Hartford	0900551350	0916051350	09160	Northwest Hills	09005	Litchfield
New Haven	0900952070	0917052070	09170	South Central Connecticut	09009	New Haven
New London	0901152350	0918052350	09180	Southeastern Connecticut	09011	New London
New Milford	0900552630	0919052630	09190	Western Connecticut	09005	Litchfield
Newington	0900352140	0911052140	09110	Capitol	09003	Hartford
Newtown	0900152980	0919052980	09190	Western Connecticut	09001	Fairfield
Norfolk	0900553470	0916053470	09160	Northwest Hills	09005	Litchfield
North Branford	0900953890	0917053890	09170	South Central Connecticut	09009	New Haven
North Canaan	0900554030	0916054030	09160	Northwest Hills	09005	Litchfield
North Haven	0900954870	0917054870	09170	South Central Connecticut	09009	New Haven
North Stonington	0901155500	0918055500	09180	Southeastern Connecticut	09011	New London
Norwalk	0900156060	0919056060	09190	Western Connecticut	09001	Fairfield
Norwich	0901156270	0918056270	09180	Southeastern Connecticut	09011	New London
Old Lyme	0901157040	0913057040	09130	Lower Connecticut River Valley	09011	New London
Old Saybrook	0900757320	0913057320	09130	Lower Connecticut River Valley	09007	Middlesex
Orange	0900957600	0917057600	09170	South Central Connecticut	09009	New Haven
Oxford	0900958300	0914058300	09140	Naugatuck Valley	09009	New Haven
Plainfield	0901559980	0915059980	09150	Northeastern Connecticut	09015	Windham
Plainville	0900360120	0911060120	09110	Capitol	09003	Hartford
Plymouth	0900560750	0914060750	09140	Naugatuck Valley	09005	Litchfield
Pomfret	0901561030	0915061030	09150	Northeastern Connecticut	09015	Windham
Portland	0900761800	0913061800	09130	Lower Connecticut River Valley	09007	Middlesex
Preston	0901162150	0918062150	09180	Southeastern Connecticut	09011	New London
Prospect	0900962290	0914062290	09140	Naugatuck Valley	09009	New Haven
Putnam	0901562710	0915062710	09150	Northeastern Connecticut	09015	Windham
Redding	0900163480	0919063480	09190	Western Connecticut	09001	Fairfield
Ridgefield	0900163970	0919063970	09190	Western Connecticut	09001	Fairfield
Rocky Hill	0900365370	0911065370	09110	Capitol	09003	Hartford
Roxbury	0900565930	0916065930	09160	Northwest Hills	09005	Litchfield
Salem	0901166210	0918066210	09180	Southeastern Connecticut	09011	New London
Salisbury	0900566420	0916066420	09160	Northwest Hills	09005	Litchfield
Scotland	0901567400	0915067400	09150	Northeastern Connecticut	09015	Windham
Seymour	0900967610	0914067610	09140	Naugatuck Valley	09009	New Haven
Sharon	0900567960	0916067960	09160	Northwest Hills	09005	Litchfield
Shelton	0900168170	0914068170	09140	Naugatuck Valley	09001	Fairfield
Sherman	0900168310	0919068310	09190	Western Connecticut	09001	Fairfield
Simsbury	0900368940	0911068940	09110	Capitol	09003	Hartford
Somers	0901369220	0911069220	09110	Capitol	09013	Tolland
South Windsor	0900371390	0911071390	09110	Capitol	09003	Hartford
Southbury	0900969640	0914069640	09140	Naugatuck Valley	09009	New Haven
Southington	0900370550	0911070550	09110	Capitol	09003	Hartford
Sprague	0901171670	0918071670	09180	Southeastern Connecticut	09011	New London
Stafford	0901372090	0911072090	09110	Capitol	09013	Tolland
Stamford	0900173070	0919073070	09190	Western Connecticut	09001	Fairfield
Sterling	0901573420	0915073420	09150	Northeastern Connecticut	09015	Windham
Stonington	0901173770	0918073770	09180	Southeastern Connecticut	09011	New London
Stratford	0900174190	0912074190	09120	Greater Bridgeport	09001	Fairfield
Suffield	0900374540	0911074540	09110	Capitol	09003	Hartford
Thomaston	0900575730	0914075730	09140	Naugatuck Valley	09005	Litchfield
Thompson	0901575870	0915075870	09150	Northeastern Connecticut	09015	Windham
Tolland	0901376290	0911076290	09110	Capitol	09013	Tolland
Torrington	0900576570	0916076570	09160	Northwest Hills	09005	Litchfield
Trumbull	0900177200	0912077200	09120	Greater Bridgeport	09001	Fairfield
Union	0901377830	0915077830	09150	Northeastern Connecticut	09013	Tolland
Vernon	0901378250	0911078250	09110	Capitol	09013	Tolland
Voluntown	0901178600	0915078600	09150	Northeastern Connecticut	09011	New London
Wallingford	0900978740	0917078740	09170	South Central Connecticut	09009	New Haven
Warren	0900579510	0916079510	09160	Northwest Hills	09005	Litchfield
Washington	0900579720	0916079720	09160	Northwest Hills	09005	Litchfield
Waterbury	0900980070	0914080070	09140	Naugatuck Valley	09009	New Haven
Waterford	0901180280	0918080280	09180	Southeastern Connecticut	09011	New London
Watertown	0900580490	0914080490	09140	Naugatuck Valley	09005	Litchfield
West Hartford	0900382590	0911082590	09110	Capitol	09003	Hartford
West Haven	0900982870	0917082870	09170	South Central Connecticut	09009	New Haven
Westbrook	0900781680	0913081680	09130	Lower Connecticut River Valley	09007	Middlesex
Weston	0900183430	0919083430	09190	Western Connecticut	09001	Fairfield
Westport	0900183500	0919083500	09190	Western Connecticut	09001	Fairfield
Wethersfield	0900384900	0911084900	09110	Capitol	09003	Hartford
Willington	0901385950	0911085950	09110	Capitol	09013	Tolland
Wilton	0900186370	0919086370	09190	Western Connecticut	09001	Fairfield
Winchester	0900586440	0916086440	09160	Northwest Hills	09005	Litchfield
Windham	0901586790	0918086790	09180	Southeastern Connecticut	09015	Windham
Windsor	0900387000	0911087000	09110	Capitol	09003	Hartford
Windsor Locks	0900387070	0911087070	09110	Capitol	09003	Hartford
Wolcott	0900987560	0914087560	09140	Naugatuck Valley	09009	New Haven
Woodbridge	0900987700	0917087700	09170	South Central Connecticut	09009	New Haven
Woodbury	0900587910	0914087910	09140	Naugatuck Valley	09005	Litchfield
Woodstock	0901588190	0915088190	09150	Northeastern Connecticut	09015	Windham

Show All

Resources for Connecticut Historical Counties

ZIP Code to County Crosswalk File: A Connecticut ZIP Code to County Crosswalk lists all current ZIP Codes from the U.S. Postal Service in CT as well as their primary Planning Region and Historical County assignments. These are actual ZIP Codes and not Census ZCTAS. This information is updated monthly to always provide the current active ZIP Codes. Fields include: ZIP Code, City, Classification, County FIPS, County name, Planning Region FIPS, Planning Region Name. Updated: January 1, 2025

ZIP+4 Code to County Crosswalk File: A Connecticut ZIP+4 to County Crosswalk lists all current ZIP+4 records from the U.S. Postal Service in CT as well as their primary Planning Region and Historical County assignments. This information is updated monthly to always provide the current active ZIP+4's. Fields include: Update Key, ZIP Code, ZIP4 Low, ZIP4 High, Region FIPS, Region Name, County FIPS, County Name. Updated: January 1, 2025

Town to County Crosswalk: The Town to County Crosswalk shows each Town in Connecticut along with it's 2020 FIPS, 2022 FIPS, Planning Region, and historical County assignment. Fields include: Town, TownFIPS2020, TownFIPS2022, PlanningRegionFIPS, PlanningRegionName, CountyFIPS, CountyName. Updated: January 21, 2025

CT County & Planning Region Boundaries Shapefile: A shape file containing the boundaries of historical Counties and Planning Regions for Connecticut together in one file can be downloaded here. Fields Included: geom, ID, StateAbbrev, StateFIPS, CountyFIPS, Name, NameLSAD, StateCountyFIPS, and LSAD. The download contains a SHP file, KML, WKT, and other popular formats.

County Shape Files: The U.S. Census provides a national county and county-equivalent shapefile which can be downloaded here. This does not include historical CT Counties. It has all U.S. counties, LA Parishes, AK Boroughs, and CT Planning Regions.

CT Planning Region Boundary Data: From the CT Geodata Portal, the CT Planning Regions includes individual polygons representing each of the 9 Planning Regions that make up the state of Connecticut.

CT Counties Boundary Data: From the CT Geodata Portal, the Connecticut Counties includes individual polygons representing each of the 8 historical counties that make up the state of Connecticut.

CT Municipalities (with FIPS) Boundary Data: From the CT Geodata Portal, the CT Municipalities (with FIPS) includes individual polygons representing each of the 169 Municipalities that make up the state of Connecticut.