ZIP codes in Day County

11 ZIPs touch Day County, South Dakota. The blue dashed line is the county border; orange ZIPs reach into it.

ZIP codes

cross the county line

7,676

people in these ZIPs

counties in SD

Most people

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Day County ZIP list

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Questions people actually ask

How many ZIP codes are in Day County, South Dakota?

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

Which ZIP code in Day County has the most people?

57274 (Webster) has about 2,621 residents, the most of any ZIP touching Day County, in the Census Bureau’s ACS 2020–2024 estimates.

Can a ZIP code be in Day 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 Day 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