ZIP codes in Jefferson County
47 ZIPs touch Jefferson County, New York. The blue dashed line is the county border; orange ZIPs reach into it.
47
ZIP codes
12
cross the county line
132,063
people in these ZIPs
62
counties in NY
Most people
Jefferson County ZIP list
More counties in New York
- Franklin County25
- Fulton County14
- Genesee County21
- Greene County42
- Hamilton County14
- Herkimer County29
- Kings County55
- Lewis County23
- Livingston County33
- Madison County33
- Monroe County69
- Montgomery County21
Questions people actually ask
How many ZIP codes are in Jefferson County, New York?
47 ZIP codes reach into Jefferson County, including 4 PO Box or single-address ZIPs placed by the town they serve. 12 of them are only partly in the county and also cover a neighboring county.
Which ZIP code in Jefferson County has the most people?
13601 (Watertown) has about 36,839 residents, the most of any ZIP touching Jefferson County, in the Census Bureau’s ACS 2020–2024 estimates.
Can a ZIP code be in Jefferson 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 Jefferson 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