| COUNTY | DATE FORMED | COUNTY SEAT | HISTORICAL DATA |
Atlantic | 1837 | Mays Landing | Formed from Gloucester County. |
Bergen | 1683 | Hackensack | Original county in East Jersey; Passaic County set off, 1837; Hudson County set off, 1840. |
Burlington | 1681 | Mount Holly | Original county in West Jersey--court established 1681; boundary set with Gloucester County, 1692; Hunterdon County set off, 1714; part of Mercer County formed from Burlington, 1838. |
Camden | 1844 | Camden | Formed from Gloucester County. |
Cape May | 1685 | Cape May
Court House | Original county in West Jersey--court established 1685; boundaries set 1692 |
Cumberland | 1748 | Bridgeton | Formed from Salem County. |
Essex | 1683 | Newark | Original county in East Jersey; part of Passaic County formed from Essex, 1837; Union County set off, 1857. |
Gloucester | 1686 | Woodbury | Original county in West Jersey--court established 1686; boundary set with Burlington County, 1692; Atlantic County set off, 1837; Camden County set off, 1844. |
Hudson | 1840 | Jersey City | Formed from Bergen County. |
Hunterdon | 1714 | Flemington | Formed from Burlington County; Morris County set off, 1739; part of Mercer County formed from Hunterdon, 1838. |
Mercer | 1838 | Trenton | Formed from Burlington, Hunterdon, Middlesex and Somerset Counties. |
Middlesex | 1683 | New Brunswick | Original county in East Jersey; Somerset County set off, 1688; part of Mercer County formed from Middlesex, 1838. |
Monmouth | 1683 | Freehold | Original county in East Jersey; Ocean County set off, 1850. |
Morris | 1739 | Morristown | Formed from Hunterdon County; Sussex County set off, 1753. |
Ocean | 1850 | Toms River | Formed from Monmouth County. |
Passaic | 1837 | Paterson | Formed from Bergen and Essex Counties. |
Salem | 1681 | Salem | Original county in West Jersey--court established 1681; formed from Salem Tenth, 1694; Cumberland set off, 1748. |
Somerset | 1688 | Somerville | Formed from Middlesex County. |
Sussex | 1753 | Newton | Formed from Morris County; Warren County set off, 1824. |
Union | 1857 | Elizabeth | Formed from Essex County. |
Warren | 1824 | Belvidere | Formed from Sussex County. |
