There are 21 counties of NJ. From north to south they range from Sussex, Passaic and Bergen to Cumberland and Cape May. Bergen is the most populous county, Salem has the fewest residents, Ocean covers the most land and Hudson is the smallest by area. Every county has a county seat, where the county government and courthouse are based, such as Hackensack for Bergen, Newark for Essex and Toms River for Ocean.
Key Takeaways
- New Jersey has 21 counties, and every town in the state belongs to one of them.
- Bergen County is the most populous, with close to 1 million residents.
- Salem County is the least populous, with about 66,000 residents.
- Ocean County is the largest by area, at about 915 square miles.
- Hudson County is the smallest by area, at about 47 square miles, and one of the most densely populated counties in the U.S.
- The oldest counties, including Bergen, Essex, Middlesex and Monmouth, date to 1683. Union, formed in 1857, is the newest.
County seats and formation years follow state and reference sources checked in September 2026. Population figures are recent U.S. Census Bureau estimates and are rounded where noted.
Full List of Counties of NJ
| County | County seat | Formed | Population (recent Census estimate) | Area (sq mi) |
|---|---|---|---|---|
| Atlantic | Mays Landing | 1837 | 278,657 | 561 |
| Bergen | Hackensack | 1683 | 977,026 | 234 |
| Burlington | Mount Holly | 1694 | 481,439 | 805 |
| Camden | Camden | 1844 | 535,799 | 222 |
| Cape May | Cape May Court House | 1692 | 93,390 | 255 |
| Cumberland | Bridgeton | 1748 | 157,148 | 489 |
| Essex | Newark | 1683 | 896,379 | 126 |
| Gloucester | Woodbury | 1686 | 312,638 | 325 |
| Hudson | Jersey City | 1840 | 735,033 | 47 |
| Hunterdon | Flemington | 1714 | 131,781 | 430 |
| Mercer | Trenton | 1838 | 399,289 | 226 |
| Middlesex | New Brunswick | 1683 | 883,335 | 311 |
| Monmouth | Freehold Borough | 1683 | 651,035 | 472 |
| Morris | Morristown | 1739 | 524,251 | 469 |
| Ocean | Toms River | 1850 | 673,746 | 915 |
| Passaic | Paterson | 1837 | 531,624 | 185 |
| Salem | Salem | 1694 | 66,280 | 338 |
| Somerset | Somerville | 1688 | 356,486 | 305 |
| Sussex | Newton | 1753 | 148,063 | 521 |
| Union | Elizabeth | 1857 | 601,863 | 103 |
| Warren | Belvidere | 1824 | 112,953 | 358 |
Area figures are rounded. Population estimates change every year, so check the Census Bureau for the newest numbers.
Counties of NJ by Region
New Jerseyans usually talk about three broad regions: North Jersey, Central Jersey and South Jersey. The borders are informal, and people often debate whether Central Jersey exists at all. Still, the grouping below is a common way to picture the map.
| Region | Counties | What the area is known for |
|---|---|---|
| North Jersey | Bergen, Essex, Hudson, Morris, Passaic, Sussex, Union, Warren | New York City suburbs, dense cities and the mountains and lakes of the Skylands |
| Central Jersey | Hunterdon, Mercer, Middlesex, Monmouth, Somerset | The state capital, Rutgers and Princeton universities, and the northern Jersey Shore |
| South Jersey | Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester, Ocean, Salem | Philadelphia suburbs, the Pine Barrens, farmland and most Jersey Shore beach towns |
Ocean County is sometimes grouped with Central Jersey and Mercer with South Jersey, depending on who you ask.
Largest and Smallest Counties of NJ
| Measure | County | Figure |
|---|---|---|
| Most populous | Bergen | 977,026 |
| Least populous | Salem | 66,280 |
| Largest land area | Ocean | About 915 sq mi |
| Smallest land area | Hudson | About 47 sq mi |
| Oldest (formed 1683) | Bergen, Essex, Middlesex, Monmouth | 1683 |
| Newest | Union | 1857 |
Hudson County packs more than 700,000 people into about 47 square miles, which makes it one of the most densely populated counties in the country. By contrast, Ocean County spreads over roughly 915 square miles, from Pine Barrens forest to barrier islands such as Long Beach Island.
Five Most Populous Counties
- Bergen County (977,026): suburbs across the Hudson River from Manhattan, with Hackensack as the county seat.
- Essex County (896,379): home to Newark, the largest city in New Jersey.
- Middlesex County (883,335): includes New Brunswick, Edison and Woodbridge.
- Hudson County (735,033): includes Jersey City, Hoboken and Bayonne.
- Ocean County (673,746): includes Toms River, Lakewood and Brick.
What Counties Do in New Jersey
In New Jersey, most daily services come from municipalities, such as police, trash pickup and local roads. However, the counties of NJ handle several important jobs of their own:
- County courts and prosecutors: each county has a prosecutor’s office and a Superior Court vicinage (some vicinages cover more than one county).
- County clerks: they record deeds, run elections with the board of elections and issue passports at many offices.
- Surrogate’s Court: the county surrogate handles wills, estates and adoptions.
- County roads, parks and colleges: counties maintain county routes, park systems and community colleges.
- County jails and social services: counties run correctional facilities and welfare agencies, which also process programs such as SNAP.
County government in New Jersey
Most counties are run by an elected Board of County Commissioners. Before 2021, commissioners were called “freeholders,” a title dating back to colonial times, but a state law changed the name. A few counties, such as Essex, Hudson, Mercer and Atlantic, also have an elected county executive.
How Counties Relate to Towns
New Jersey has 564 municipalities, and every one of them sits in a single county. Towns keep their own governments, so moving between two towns in the same county can still change your property tax rate, school district and local rules. As a result, knowing your county matters most for courts, deeds, county parks, county colleges and many social services.
Fun Facts About the Counties of NJ
- Cape May Court House is the county seat of Cape May County, not the city of Cape May.
- Mays Landing, the Atlantic County seat, is part of Hamilton Township rather than a separate town.
- Salem County is one of the least populous counties in New Jersey but is rich in farmland and colonial history.
- Four counties share the oldest date, 1683, when the colony of East Jersey created its first counties.
- Union County was split from Essex County in 1857, making it the newest county.
Counties of NJ Ranked by Population
| Rank | County | Population (recent estimate) |
|---|---|---|
| 1 | Bergen | 977,026 |
| 2 | Essex | 896,379 |
| 3 | Middlesex | 883,335 |
| 4 | Hudson | 735,033 |
| 5 | Ocean | 673,746 |
| 6 | Monmouth | 651,035 |
| 7 | Union | 601,863 |
| 8 | Camden | 535,799 |
| 9 | Passaic | 531,624 |
| 10 | Morris | 524,251 |
| 11 | Burlington | 481,439 |
| 12 | Mercer | 399,289 |
| 13 | Somerset | 356,486 |
| 14 | Gloucester | 312,638 |
| 15 | Atlantic | 278,657 |
| 16 | Cumberland | 157,148 |
| 17 | Sussex | 148,063 |
| 18 | Hunterdon | 131,781 |
| 19 | Warren | 112,953 |
| 20 | Cape May | 93,390 |
| 21 | Salem | 66,280 |
How to Find Your County in New Jersey
If you are not sure which of the counties of NJ you live in, there are a few quick ways to check. Your property tax bill lists your municipality and county, and so do voter registration notices from your county clerk. In addition, your town’s official website usually names its county on the home page. Finally, our list of towns by county, linked below, shows every municipality and the county it belongs to.
Knowing your county helps when you need to record a deed, file for an estate at the Surrogate’s Court, register to vote, apply for county college classes or find a county park.
Explore More of New Jersey
To find which county every town belongs to, see our full list of NJ towns by county. Trenton, the Mercer County seat, is also the state capital, as explained in our guide to the capital of NJ. Phone numbers also follow regional lines, so our NJ area codes guide is a handy companion. Browse more in our Living in NJ section or on the homepage.
Frequently Asked Questions About the Counties of NJ
How many counties are in New Jersey?
New Jersey has 21 counties.
What is the largest county in NJ by population?
Bergen County is the most populous county, with close to 1 million residents in recent Census estimates.
What is the largest county in NJ by area?
Ocean County is the largest by area, at about 915 square miles.
What is the smallest county in New Jersey?
Hudson County is the smallest by area, at about 47 square miles, while Salem County has the fewest residents.
What is the newest county in NJ?
Union County, formed from Essex County in 1857, is the newest.
What is the county seat of Cape May County?
The county seat is Cape May Court House in Middle Township, not the city of Cape May.
What are county freeholders called now?
Since 2021, New Jersey county governing boards are called Boards of County Commissioners instead of freeholders.
New Jersey’s 21 Counties at a Glance
The counties of NJ number 21, from Sussex in the far north to Cape May at the southern tip. Bergen has the most people, Salem the fewest, Ocean the most land and Hudson the least. Each county has a seat that hosts its courts and government offices, so knowing your county helps with everything from recording a deed to finding a county park.
