List of New Jersey counties

1. Atlantic County: formed in 1837 from part of Gloucester County. County seat: Mays Landing.
2. Bergen County: one of four original counties created in East Jersey in 1683. County seat: Hackensack.
3. Burlington County: formed in 1694 by West Jersey. County seat: Mount Holly.
4. Camden County: formed in 1844 from part of Gloucester County. County seat: Camden.
5. Cape May County: formed in 1692 by West Jersey. County seat: Cape May Court House.
6. Cumberland County: formed in 1748 from part of Salem County. County seat: Bridgeton.
7. Essex County: one of four original counties created in East Jersey in 1683. County seat: Newark.
8. Gloucester County: formed in 1686 by West Jersey. County seat: Woodbury.
9. Hudson County: formed in 1840 from part of Bergen County. County seat: Jersey City.
10. Hunterdon County: formed in 1714 from part of Burlington County. County seat: Flemington.
11. Mercer County: formed in 1838 from parts of Burlington County, Hunterdon County, Middlesex County, and Somerset County. County seat: Trenton.
12. Middlesex County: one of four original counties created in East Jersey in 1683. County seat: New Brunswick.
13. Monmouth County: one of four original counties created in East Jersey in 1683. County seat: Freehold.
14. Morris County: formed in 1739 from part of Hunterdon County. County seat: Morristown.
15. Ocean County: formed in 1850 from part of Monmouth County. County seat: Toms River.
16. Passaic County
17. Salem County: formed in 1694 by West Jersey. County seat: Salem.
18. Somerset County: formed in 1688 from part of Middlesex County. County seat: Somerville.
19. Sussex County: formed in 1753 from part of Morris County. County seat: Newton.
20. Union County: formed in 1857 from part of Essex County. County seat: Elizabeth.
21. Warren County: formed in 1824 from part of Sussex County. County seat: Belvidere.