ZIP codes in LaSalle County
29 ZIPs touch LaSalle County, Illinois. The blue dashed line is the county border; orange ZIPs reach into it.
29
ZIP codes
15
cross the county line
125,872
people in these ZIPs
102
counties in IL
Most people
LaSalle County ZIP list
More counties in Illinois
- Jo Daviess County15
- Johnson County12
- Kane County40
- Kankakee County22
- Kendall County19
- Knox County23
- Lake County40
- Lawrence County7
- Lee County24
- Livingston County29
- Logan County20
- Macon County29
Questions people actually ask
How many ZIP codes are in LaSalle County, Illinois?
29 ZIP codes reach into LaSalle County. 15 of them are only partly in the county and also cover a neighboring county.
Which ZIP code in LaSalle County has the most people?
61350 (Ottawa) has about 23,713 residents, the most of any ZIP touching LaSalle County, in the Census Bureau’s ACS 2020–2024 estimates.
Can a ZIP code be in LaSalle 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 LaSalle 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