Middlesex County, CT ZIP codes
There are 23 ZIP codes in Middlesex County, CT, in 22 towns, from 06409 to 06498. The largest are 06457 (Middletown), 06416 (Cromwell) and 06413 (Clinton).
Connecticut abolished county government in 1960, and since 2022 the Census Bureau counts nine planning regions instead of its eight counties. Middlesex County has no government of its own, but the counties are still how Connecticut's towns and ZIP codes are placed. Its ZIP codes lie in the Lower Connecticut River Valley planning region.
- ZIP codes
- 23
- Towns
- 22
- County FIPS
09007- State
- Connecticut
- Population
- 165,364
- Land area
- 369 sq mi
Land area from the Census Bureau's 2020 Gazetteer, the last to list Middlesex County. Population is the sum of the ZIP codes listed here (American Community Survey 2020–2024), since the Bureau now counts Connecticut by planning region.
Middlesex County ZIP codes by town
Each ZIP code is listed under the county most of its land lies in and the town the Postal Service names it for; a ZIP code's own page shows exactly how it is split.
Map of Middlesex County ZIP codes
The ZIP codes of Middlesex County, shaded. Outlines are Census ZIP Code Tabulation Areas (2020), which approximate the mail routes; PO-box and single-address codes have no area and are not drawn. Click any area to open its ZIP code.
Middlesex County in numbers
About 165,364 people live in Middlesex County, in 69,622 households, the 6th most populous of Connecticut's 8 counties.
| Population | 165,364 |
|---|---|
| Households | 69,622 |
| Population density | 448 / sq mi |
U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates, summed over the 23 ZIP codes listed here, as the Bureau no longer publishes figures for Middlesex County; medians do not add up and are left out. Survey estimates carry margins of error, wider for small places. Sources and methods.
Largest towns in Middlesex County
| Town | ZIP codes | Population |
|---|---|---|
| Middletown | 2 | 47,958 |
| Cromwell | 1 | 14,334 |
| Old Saybrook | 1 | 10,575 |
| Westbrook | 1 | 6,856 |
| Killingworth | 1 | 6,240 |
| Portland | 1 | 5,944 |
| East Haddam | 1 | 5,182 |
| Deep River | 1 | 4,458 |
| Chester | 1 | 3,825 |
| Clinton | 1 | 3,465 |
| Durham | 1 | 3,347 |
| East Hampton | 1 | 3,347 |
| Essex | 1 | 3,267 |
| Haddam | 1 | 2,887 |
| Ivoryton | 1 | 2,826 |
Population of the census place of that name where there is one, otherwise of the ZIP codes the Postal Service addresses by it. A town's ZIP codes can reach past the county line.
Neighbouring counties
Counties that share a ZIP code with Middlesex County.
Not sure you are in Middlesex County? What county am I in? answers from your location, near a county line included.
Every ZIP code in Middlesex County, with figures
| ZIP | City | Type | Population | Median income | Median home |
|---|---|---|---|---|---|
06409 | Centerbrook , CT | Standard | 701 | $107,909 | $387,300 |
06412 | Chester , CT | Standard | 3,825 | $109,191 | $442,200 |
06413 | Clinton , CT | Standard | 13,377 | $124,824 | $380,000 |
06414 | Cobalt , CT | Standard | 302 | $131,090 | $356,000 |
06416 | Cromwell , CT | Standard | 14,334 | $110,596 | $325,200 |
06417 | Deep River , CT | Standard | 4,458 | $90,253 | $362,200 |
06419 | Killingworth , CT | Standard | 6,240 | $140,655 | $446,200 |
06422 | Durham , CT | Standard | 7,208 | $158,857 | $424,800 |
06423 | East Haddam , CT | Standard | 5,182 | $107,549 | $373,700 |
06424 | East Hampton , CT | Standard | 12,751 | $123,680 | $347,800 |
06426 | Essex , CT | Standard | 3,267 | $103,705 | $729,200 |
06438 | Haddam , CT | Standard | 2,887 | $121,429 | $362,500 |
06441 | Higganum , CT | Standard | 5,348 | $111,250 | $393,100 |
06442 | Ivoryton , CT | Standard | 2,826 | $104,358 | $468,200 |
06455 | Middlefield , CT | Standard | 2,480 | $104,180 | $388,700 |
06456 | Middle Haddam , CT | Standard | 281 | $128,542 | $434,000 |
06457 | Middletown , CT | Standard | 46,720 | $79,463 | $295,300 |
06459 | Middletown , CT | Standard | 1,238 | — | — |
06469 | Moodus , CT | Standard | 3,311 | $104,888 | $300,000 |
06475 | Old Saybrook , CT | Standard | 10,575 | $114,333 | $538,200 |
06480 | Portland , CT | Standard | 9,434 | $118,929 | $337,400 |
06481 | Rockfall , CT | Standard | 1,763 | $84,674 | $360,400 |
06498 | Westbrook , CT | Standard | 6,856 | $91,202 | $434,300 |
Cite this page
zipcodes.pro. “Middlesex County ZIP codes.” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/state/ct/county/middlesex
Underlying data is public domain or openly licensed — sources, vintages and licences.