Mercer County, New Jersey
Mercer County is a county in New Jersey. Its county FIPS code is 34021. Use the boundary map and neighboring areas below to check the jurisdiction you need.
- Official code
- 34021
- Representative coordinates
- 40.282503, -74.703724
- County type
- County
- County seat or government
- Trenton
- Resident population, July 2025
- 399,289
- Land area
- 581.405 km²
- Water area
- 11.328 km²
- State
- New Jersey
The representative point identifies this area. It is not a street address or a boundary survey.
Time zones in Mercer County
| Time zone | Local time and UTC offset | Next clock change |
|---|---|---|
| America/New_York | UTC-05:00 in January; UTC-04:00 in July. Enable JavaScript for the live clock. | Enable JavaScript for upcoming changes. |
Listed zones overlap the mapped area. A point lookup can distinguish sides of a boundary. Your device’s zone may differ.
Census ZIP areas
08501 · 08512 · 08520 · 08525 · 08530 · 08534 · 08540 · 08542 · 08544 · 08550 · 08558 · 08560 · 08561 · 08608 · 08609 · 08610 · 08611 · 08618 · 08619 · 08620 · 08628 · 08629 · 08638 · 08648 · 08690 · 08691
These statistical areas overlap the boundary. They are not delivery assignments; confirm mailing details with USPS ZIP Code Lookup.
Official county information
Mercer County government website ↗ is the next stop for county offices, tax, voting, jury and records information. A geographic lookup cannot determine eligibility, tax liability or a court obligation.
Cities, towns and communities
These areas overlap the mapped boundary; an overlap does not mean that every address belongs to both.
- Groveville CDP, NJ
- Hamilton Square CDP, NJ
- Hightstown borough, NJ
- Hopewell borough, NJ
- Lawrenceville CDP, NJ
- Mercerville CDP, NJ
- Pennington borough, NJ
- Princeton, NJ
- Princeton Junction CDP, NJ
- Robbinsville Center CDP, NJ
- The College of New Jersey CDP, NJ
- Titusville CDP, NJ
- Trenton city, NJ
- Twin Rivers CDP, NJ
- Washington Crossing CDP, NJ
- White Horse CDP, NJ
- Windsor CDP, NJ
- Yardville CDP, NJ
Areas sharing the mapped boundary
These areas touch this mapped boundary.
Before using this answer on a form
Use a precise point for address-level questions. A device accuracy circle can cross a boundary; confirm tax, voting or jury details with the responsible office.
Find the county at your current point, check its ZIP area, or find its physical time zone.