Union County, New Jersey

Union County is a county in New Jersey, United States, about 8 miles southwest of Newark and roughly 20 miles from Midtown Manhattan. It had a population of 575,345 at the 2020 census, an estimated 601,863 by 2025, and covers 105.41 square miles (273.0 km2) centred near 40°39′N 74°17′W.

Elizabeth is the county seat and the county’s largest city; its postal code is 07201. The county holds 21 municipalities — 5 cities, 1 town, 8 townships and 7 boroughs — and every one of them is fully incorporated, since New Jersey has no unincorporated territory. The county runs on Eastern Time. Its FIPS code is 34039.

Towns & Villages in Union County

Union County has 21 named places on record, and all 21 are incorporated municipalities: 5 cities, 1 town, 8 townships and 7 boroughs. New Jersey abolished unincorporated territory statewide in the 19th century, so there are no CDPs or unincorporated communities here — every place in this table runs its own local government.

Winfield Township, the smallest municipality on the list, has no ZIP code of its own; it shares Linden’s 07036, because the township’s roughly half-square-mile of land sits entirely inside Linden’s borders. Elizabeth, the seat, is large enough to carry four ZIP codes of its own (07201, 07202, 07206 and 07208), and its Elizabethport waterfront neighborhood is addressed under 07206.

ZIP Codes

• 07201 — Elizabeth (downtown and city hall)
• 07202 — Elizabeth
• 07206 — Elizabeth (Elizabethport)
• 07208 — Elizabeth
• 07207 — Elizabeth (post office box ZIP only)
• 07060 — Plainfield
• 07062 — Plainfield
• 07063 — Plainfield
• 07061 — Plainfield (post office box ZIP only)
• 07036 — Linden (also serves Winfield Township)
• 07065 — Rahway
• 07090 — Westfield
• 07091 — Westfield (post office box ZIP only)
• 07076 — Scotch Plains
• 07016 — Cranford
• 07203 — Roselle
• 07205 — Hillside
• 07081 — Springfield
• 07066 — Clark
• 07204 — Roselle Park
• 07974 — New Providence
• 07922 — Berkeley Heights
• 07033 — Kenilworth
• 07023 — Fanwood
• 07092 — Mountainside
• 07027 — Garwood
• 07901 — Summit
• 07902 — Summit (post office box ZIP only)
• 07083 — Union
• 07088 — Vauxhall, a neighborhood split between Union Township and Hillside Township

Only Winfield Township has no ZIP delivery area of its own among the county’s 21 municipalities; its residents use Linden addresses.

Geography

Union County crosses two distinct landscapes. Its western third rises into the First and Second Watchung Mountains, wooded basalt ridges running through Berkeley Heights, Springfield and Scotch Plains, while its eastern third flattens into tidal marsh and industrial waterfront along the Arthur Kill and Newark Bay at Elizabeth and Linden. Of the county’s 105.41 square miles, 102.77 are land and 2.64 are water, about 2.5 percent — concentrated in the Arthur Kill, the tidal strait separating Elizabeth and Linden from Staten Island, and in the Rahway River, which drains the county’s center before reaching the Arthur Kill at Rahway.

Essex County lies to the north, Morris County touches the county’s northwest corner, Somerset County borders it to the west, and Middlesex County lies to the south. Essex County, Morris County, Somerset County and Middlesex County all border Union directly.

Demographics

Union County had a population of 575,345 at the 2020 census, and the latest estimate puts the county near 601,863 residents. Elizabeth and Union Township are by far the two largest communities, together holding more than a third of the county’s population. Median household income runs $103,202, above New Jersey’s statewide figure of $99,781. Population density works out to roughly 5,600 people per square mile of land, among the densest counties in the United States and one reason the county has no unincorporated land left to develop.

Economy & Local Life

Health care and social assistance employs the most county residents, about 37,212 workers, followed by educational services at 28,693 and retail trade at 28,624. Merck & Co. returned its global corporate headquarters to Rahway in 2024, making the pharmaceutical company the county’s largest single private employer. Kean University, founded in 1855 and straddling Union Township and Hillside, enrolls nearly 13,000 undergraduates. Port Newark–Elizabeth Marine Terminal, one of the busiest container ports on the US East Coast, sits inside Elizabeth’s city limits and anchors a large logistics and warehousing sector along the Turnpike corridor. The county’s largest annual civic event is the Union County Means Business Expo, held each September at Kean University in Union Township.

History

The New Jersey Legislature created Union County on 19 March 1857, the last of the state’s 21 counties to be organized, carving it out of Essex County. The name was a deliberate statement: with the country splitting over slavery on the eve of the Civil War, the new county’s founders named it for the national Union rather than for a person or place.

The county’s most significant historical event predates its own founding by 77 years. On 23 June 1780, British and Hessian troops under General Wilhelm von Knyphausen marched through Springfield toward Washington’s army at Morristown. American Continental troops and New Jersey militia repelled the attack in the Battle of Springfield, ending the last major British offensive in New Jersey. George Washington later praised the militia’s performance as equal to any troops he had seen in the war.

Getting There

Interstate 78 crosses the county east to west through Union Township, Springfield and Berkeley Heights. Interstate 278 begins in Elizabeth at the Goethals Bridge to Staten Island, and the New Jersey Turnpike (Interstate 95) and Garden State Parkway both run north to south through the county’s eastern half. US 1/9 and US 22 also cross the county.

• Newark — about 8 miles northeast
• New York City — about 20 miles northeast
• New Brunswick — about 15 miles southwest
• Plainfield to Elizabeth — about 10 miles east

Newark Liberty International Airport, whose runways sit largely within Elizabeth’s city limits, is the county’s own commercial airport and one of the busiest in the country. Newark Penn Station, about 8 miles northeast in Essex County, is the nearest Amtrak stop; NJ Transit’s Northeast Corridor and Raritan Valley lines serve local stations at Elizabeth, Linden, Rahway, Westfield, Cranford and Summit.

Frequently Asked Questions

Where is Union County located?
It sits in northern New Jersey, about 8 miles southwest of Newark and 20 miles from Manhattan, bordered by Essex, Morris, Somerset and Middlesex counties.

What is the population of Union County?
575,345 at the 2020 census, with an estimate near 601,863 by 2025.

How big is Union County?
105.41 square miles (273.0 km2), of which 102.77 square miles are land.

What is the county seat of Union County?
Elizabeth, organized in 1857 alongside the county itself, is the county seat and largest city.

How many towns and cities are in Union County?
21 municipalities: 5 cities (Elizabeth, Linden, Plainfield, Rahway and Summit), 1 town (Westfield), 8 townships and 7 boroughs. All are incorporated — New Jersey has no unincorporated communities.

What ZIP codes does Union County use?
30 ZIP codes in all, from 07016 in Cranford and 07033 in Kenilworth to 07201 through 07208 across Elizabeth and 07901 in Summit; a full list is above.

What is Union County known for?
Port Newark–Elizabeth Marine Terminal, one of the East Coast’s busiest container ports, and the 1780 Battle of Springfield, a Revolutionary War victory that ended British ambitions in New Jersey.

More counties in this state: Towns and villages in New Jersey.