ZIP codes in Foster County

8 ZIPs touch Foster County, North Dakota. The blue dashed line is the county border; orange ZIPs reach into it.

ZIP codes

cross the county line

5,762

people in these ZIPs

counties in ND

Most people

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Foster County ZIP list

More counties in North Dakota

All 53 counties in North Dakota

Questions people actually ask

How many ZIP codes are in Foster County, North Dakota?

8 ZIP codes reach into Foster County. 7 of them are only partly in the county and also cover a neighboring county.

Which ZIP code in Foster County has the most people?

58421 (Carrington) has about 2,969 residents, the most of any ZIP touching Foster County, in the Census Bureau’s ACS 2020–2024 estimates.

Can a ZIP code be in Foster 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 Foster 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.

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