ZIP codes in Knox County

17 ZIPs touch Knox County, Ohio. The blue dashed line is the county border; orange ZIPs reach into it.

17

ZIP codes

12

cross the county line

94,237

people in these ZIPs

88

counties in OH

Most people

Knox County ZIP list

Questions people actually ask

How many ZIP codes are in Knox County, Ohio?

17 ZIP codes reach into Knox County, including 1 PO Box or single-address ZIPs placed by the town they serve. 12 of them are only partly in the county and also cover a neighboring county.

Which ZIP code in Knox County has the most people?

43050 (Mount Vernon) has about 31,074 residents, the most of any ZIP touching Knox County, in the Census Bureau’s ACS 2020–2024 estimates.

Can a ZIP code be in Knox 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 Knox 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