ZIP codes in New Haven County

78 ZIPs touch New Haven County, Connecticut. The blue dashed line is the county border; orange ZIPs reach into it.

78

ZIP codes

1

cross the county line

867,469

people in these ZIPs

8

counties in CT

Most people

New Haven County ZIP list

Questions people actually ask

How many ZIP codes are in New Haven County, Connecticut?

78 ZIP codes reach into New Haven County, including 37 PO Box or single-address ZIPs placed by the town they serve. 1 of them are only partly in the county and also cover a neighboring county.

Which ZIP code in New Haven County has the most people?

06516 (West Haven) has about 55,351 residents, the most of any ZIP touching New Haven County, in the Census Bureau’s ACS 2020–2024 estimates.

Can a ZIP code be in New Haven County and another county?

Yes. ZIP codes follow mail routes, not county lines. Rows marked with a percentage show how much of that ZIP’s land is in New Haven County. For one address, pin the exact spot on the ZIP finder to see its county.

Where does this list come from?

ZIP areas and their county overlaps come from the Census Bureau’s 2020 ZIP Code Tabulation Area to county relationship file. PO Box ZIPs have no area, so each is placed in the county of the ZIP area nearest the town it serves.

Updated 2026-11-10 · Where the data comes from