| Counties of NewJersey | |
|---|---|
Clickable map ofNew Jersey counties | |
| Location | New Jersey |
| Number | 21 |
| Populations | 65,874 (Salem) – 978,641 (Bergen) |
| Areas | 47 square miles (120 km2) (Hudson) – 805 square miles (2,080 km2) (Burlington) |
| Government | |
| Subdivisions |
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There are 21counties in the U.S. state ofNew Jersey. These counties together contain 564municipalities, oradministrative entities composed of clearly defined territory; 253boroughs, 52cities, 15towns, 240townships, and 4villages.[1] In New Jersey, a county is a local level of government between the state and municipalities. County government in New Jersey includes aBoard of County Commissioners,[2] sheriff, clerk, andsurrogate (responsible for uncontested and routine probate),[3] all of which are elected positions. Counties organized under the Optional County Charter Law may also have an electedcounty executive.[4] Counties traditionally perform state-mandated duties such as the maintenance of jails, parks, and certain roads.[5] The site of a county's administration and courts is called thecounty seat.
New Jersey was governed by two groups of proprietors as two distinct provinces,East Jersey andWest Jersey, between 1674 and 1702. New Jersey's first counties were created as administrative districts within each province, with East Jersey split in 1675 intoBergen,Essex,Middlesex andMonmouth counties, while West Jersey's initial counties ofBurlington andSalem date to 1681.[6][7] The most recent county created in New Jersey isUnion County, created in 1857 and named after the union of the United States when theCivil War was imminent. New Jersey's county names derive from several sources, though most of its counties are named after place names inEngland and prominent leaders in the colonial and revolutionary periods.Bergen County is the most populous county—as of the 2020 Census—with 955,732 people, whileSalem County is the least populous with 64,837 people.

Until the 1960s, theNew Jersey Senate had 21 representatives, one from each county regardless of population. In the wake of the 1964 decision by theSupreme Court of the United States inReynolds v. Sims, establishing theone man, one vote principle that state legislative districts must be approximately equal in size,David Friedland filed suit inNew Jersey Supreme Court on behalf of two union leaders, challenging a system under which each county was represented by a single member in theNew Jersey Senate. The court ruled unanimously that the existing system was unconstitutional, ordered that interim measures be established by statute for the 1965 legislative elections, and ordered that the needed constitutional changes to restructure theNew Jersey Legislature to be in compliance with "one man, one vote" requirements be in place before elections took place in 1967.[8] The senate unilaterally—by internal rule, not by statute—enacted a proposal whereby each senator's vote would be weighted based on the population of the county represented, under whichCape May County's senator would receive one vote while the senator fromEssex County would receive 19.1 votes, in direct relation to the ratio of residents between counties.[9] The Supreme Court ruled unanimously that it was unconstitutional for the senate to adopt a weighted voting system unilaterally.[9][10] In 1966, the constitution was amended to establish 40 districts statewide, each represented by one senator and two assembly members, without relation to county boundaries.[11]

TheFederal Information Processing Standard (FIPS) code, used by the United States government to uniquely identify counties, is provided with each entry. FIPS codes are five-digit numbers; for New Jersey the codes start with 34 and are completed with the three-digit county code. The FIPS code for each county in the table links to census data for that county.[12]
| County | FIPS code[12] | County seat[13] | Largest City[14] | Est.[13] | Formed from[6][7] | Named for[15] | Density (per mi2) | Pop.[16] | Area[13] | Map |
|---|---|---|---|---|---|---|---|---|---|---|
| Atlantic County | 001 | Mays Landing | Egg Harbor Township 47,842 | 1837 | Gloucester County | TheAtlantic Ocean, which forms the county's eastern border | 497.53 | 279,114 | 561 sq mi (1,453 km2) | |
| Bergen County | 003 | Hackensack | Hackensack 46,030 | 1683 | One of four original counties created inEast Jersey | Bergen, New Netherland settlement | 4,182.23 | 978,641 | 234 sq mi (606 km2) | |
| Burlington County | 005 | Mount Holly | Evesham Township 46,826 | 1694 | One of two original counties created inWest Jersey | The old ancient name for an inland market nearBridlington, England | 590.70 | 475,515 | 805 sq mi (2,085 km2) | |
| Camden County | 007 | Camden | Cherry Hill 74,553 | 1844 | Gloucester County | Charles Pratt, 1st Earl Camden (1714–1794), an English supporter of the colonists during the American Revolution[17] | 2,405.35 | 533,988 | 222 sq mi (575 km2) | |
| Cape May County | 009 | Cape May Court House | Lower Township 22,057 | 1692 | Burlington County | Cape May, named in turn for the 17th-century Dutch explorerCornelius Jacobsen Mey, who explored and surveyed theDelaware Bay to the south of the county | 368.14 | 93,875 | 255 sq mi (660 km2) | |
| Cumberland County | 011 | Bridgeton | Vineland 60,780 | 1748 | Salem County | Prince William, Duke of Cumberland (1721–1765), second son ofGeorge II of Great Britain and military victor at theBattle of Culloden in 1746 | 318.36 | 155,678 | 489 sq mi (1,267 km2) | |
| Essex County | 013 | Newark | Newark 311,549 | 1683 | One of four original counties created inEast Jersey | The county ofEssex in England | 6,996.25 | 881,527 | 126 sq mi (326 km2) | |
| Gloucester County | 015 | Woodbury | Washington Township 48,677 | 1686 | Burlington County | The city ofGloucester, England | 959.33 | 311,783 | 325 sq mi (842 km2) | |
| Hudson County | 017 | Jersey City | Jersey City 292,449 | 1840 | Bergen County | The English explorerHenry Hudson (d. 1611), who explored portions of New Jersey's coastline | 15,663.51 | 736,185 | 47 sq mi (122 km2) | |
| Hunterdon County | 019 | Flemington | Raritan Township 23,447 | 1714 | Burlington County | Robert Hunter (1664–1734), the Colonial Governor of New Jersey from 1710 to 1720 | 306.30 | 131,708 | 430 sq mi (1,114 km2) | |
| Mercer County | 021 | Trenton | Hamilton Township 92,297 | 1838 | Burlington, Hunterdon, Middlesex, and Somerset counties | TheContinental ArmyGeneralHugh Mercer (1726–1777), who died at theBattle of Princeton[18] | 1,735.12 | 392,138 | 226 sq mi (585 km2) | |
| Middlesex County | 023 | New Brunswick | Edison 107,588 | 1683 | One of four original counties created inEast Jersey | The historic county ofMiddlesex in England | 2,862.12 | 890,119 | 311 sq mi (805 km2) | |
| Monmouth County | 025 | Freehold Borough | Middletown Township 67,106 | 1683 | One of four original counties created inEast Jersey | The historicCounty of Monmouth inGreat Britain | 1,371.86 | 647,520 | 472 sq mi (1,222 km2) | |
| Morris County | 027 | Morristown | Parsippany-Troy Hills 56,162 | 1739 | Hunterdon County | ColonelLewis Morris (1671–1746), colonial governor ofNew Jersey at the time of the county's formation[19][20] | 1,115.25 | 523,053 | 469 sq mi (1,215 km2) | |
| Ocean County | 029 | Toms River | Lakewood Township 135,158 | 1850 | Monmouth and Burlington counties | TheAtlantic Ocean, which forms the eastern border of New Jersey | 1,047.85 | 666,434 | 915 sq mi (2,370 km2) | |
| Passaic County | 031 | Paterson | Paterson 159,732 | 1837 | Bergen and Essex counties | Pasaeck, aLenape word meaning "valley" | 2,846.47 | 526,597 | 185 sq mi (479 km2) | |
| Salem County | 033 | Salem | Pennsville Township 12,684 | 1694 | One of two original counties created inWest Jersey | Salem, Biblical town, which takes its name from theHebrew word for "peace." | 194.89 | 65,874 | 338 sq mi (875 km2) | |
| Somerset County | 035 | Somerville | Franklin Township 68,364 | 1688 | Middlesex County | The county ofSomerset in England | 1,172.02 | 357,467 | 305 sq mi (790 km2) | |
| Sussex County | 037 | Newton | Vernon Township 22,358 | 1753 | Morris County | The county ofSussex in England | 283.00 | 147,444 | 521 sq mi (1,349 km2) | |
| Union County | 039 | Elizabeth | Elizabeth 137,298 | 1857 | Essex County | The union of the United States, which was being threatened by the dispute over slavery | 5,768.54 | 594,160 | 103 sq mi (267 km2) | |
| Warren County | 041 | Belvidere | Phillipsburg 15,249 | 1824 | Sussex County | TheAmerican Revolutionary War GeneralJoseph Warren (1741–1775), killed at theBattle of Bunker Hill | 312.94 | 112,031 | 358 sq mi (927 km2) |