ZIP codes in Butler County

18 ZIPs touch Butler County, Iowa. The blue dashed line is the county border; orange ZIPs reach into it.

ZIP codes

cross the county line

76,878

people in these ZIPs

counties in IA

Most people

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Butler County ZIP list

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Questions people actually ask

How many ZIP codes are in Butler County, Iowa?

18 ZIP codes reach into Butler County. 13 of them are only partly in the county and also cover a neighboring county.

Which ZIP code in Butler County has the most people?

50613 (Cedar Falls) has about 43,867 residents, the most of any ZIP touching Butler County, in the Census Bureau’s ACS 2020–2024 estimates.

Can a ZIP code be in Butler 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 Butler 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