ZIP codes in Clinton County
18 ZIPs touch Clinton County, Illinois. The blue dashed line is the county border; orange ZIPs reach into it.
18
ZIP codes
9
cross the county line
75,469
people in these ZIPs
102
counties in IL
Most people
Clinton County ZIP list
More counties in Illinois
- Carroll County11
- Cass County9
- Champaign County39
- Christian County20
- Clark County11
- Clay County13
- Coles County17
- Cook County228
- Crawford County11
- Cumberland County12
- De Witt County13
- DeKalb County22
Questions people actually ask
How many ZIP codes are in Clinton County, Illinois?
18 ZIP codes reach into Clinton County, including 1 PO Box or single-address ZIPs placed by the town they serve. 9 of them are only partly in the county and also cover a neighboring county.
Which ZIP code in Clinton County has the most people?
62801 (Centralia) has about 19,827 residents, the most of any ZIP touching Clinton County, in the Census Bureau’s ACS 2020–2024 estimates.
Can a ZIP code be in Clinton 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 Clinton 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