ZIP codes in Union County
31 ZIPs touch Union County, New Jersey. The blue dashed line is the county border; orange ZIPs reach into it.
31
ZIP codes
4
cross the county line
616,275
people in these ZIPs
21
counties in NJ
Most people
Union County ZIP list
More counties in New Jersey
- Morris County64
- Ocean County33
- Passaic County43
- Salem County15
- Somerset County38
- Sussex County29
- Warren County25
Questions people actually ask
How many ZIP codes are in Union County, New Jersey?
31 ZIP codes reach into Union County, including 4 PO Box or single-address ZIPs placed by the town they serve. 4 of them are only partly in the county and also cover a neighboring county.
Which ZIP code in Union County has the most people?
07083 (Union) has about 58,170 residents, the most of any ZIP touching Union County, in the Census Bureau’s ACS 2020–2024 estimates.
Can a ZIP code be in Union 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 Union 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