ZIP codes in Allamakee County
11 ZIPs touch Allamakee County, Iowa. The blue dashed line is the county border; orange ZIPs reach into it.
11
ZIP codes
6
cross the county line
30,176
people in these ZIPs
99
counties in IA
Most people
Allamakee County ZIP list
More counties in Iowa
- Adair County14
- Adams County10
- Appanoose County11
- Audubon County12
- Benton County24
- Black Hawk County20
- Boone County23
- Bremer County13
Questions people actually ask
How many ZIP codes are in Allamakee County, Iowa?
11 ZIP codes reach into Allamakee County, including 1 PO Box or single-address ZIPs placed by the town they serve. 6 of them are only partly in the county and also cover a neighboring county.
Which ZIP code in Allamakee County has the most people?
52101 (Decorah) has about 12,706 residents, the most of any ZIP touching Allamakee County, in the Census Bureau’s ACS 2020–2024 estimates.
Can a ZIP code be in Allamakee 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 Allamakee 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