ZIP codes in Humboldt County
17 ZIPs touch Humboldt County, Iowa. The blue dashed line is the county border; orange ZIPs reach into it.
17
ZIP codes
14
cross the county line
18,346
people in these ZIPs
99
counties in IA
Most people
Humboldt County ZIP list
More counties in Iowa
- Hamilton County15
- Hancock County13
- Hardin County15
- Harrison County15
- Henry County12
- Howard County9
- Ida County12
- Iowa County22
- Jackson County16
- Jasper County21
- Jefferson County17
- Johnson County26
Questions people actually ask
How many ZIP codes are in Humboldt County, Iowa?
17 ZIP codes reach into Humboldt County. 14 of them are only partly in the county and also cover a neighboring county.
Which ZIP code in Humboldt County has the most people?
50548 (Humboldt) has about 5,722 residents, the most of any ZIP touching Humboldt County, in the Census Bureau’s ACS 2020–2024 estimates.
Can a ZIP code be in Humboldt 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 Humboldt 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