ZIP codes in Hillsborough County

39 ZIPs touch Hillsborough County, New Hampshire. The blue dashed line is the county border; orange ZIPs reach into it.

39

ZIP codes

4

cross the county line

426,425

people in these ZIPs

10

counties in NH

Most people

Hillsborough County ZIP list

Questions people actually ask

How many ZIP codes are in Hillsborough County, New Hampshire?

39 ZIP codes reach into Hillsborough County, including 5 PO Box or single-address ZIPs placed by the town they serve. 4 of them are only partly in the county and also cover a neighboring county.

Which ZIP code in Hillsborough County has the most people?

03103 (Manchester) has about 37,775 residents, the most of any ZIP touching Hillsborough County, in the Census Bureau’s ACS 2020–2024 estimates.

Can a ZIP code be in Hillsborough 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 Hillsborough 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