New Jersey

Union

575,345

2020 population

1860

first census record

census records

About Union

Union, New Jersey, first appears in the United States federal census in 1860, when it recorded a population of 27,780. At the most recent census, in 2020, its population stood at 575,345.

The county's recorded population has risen across the decades to its highest level in 2020.

On the ground today, 19 documented military engagements have been recorded within the county, among them Battle of Springfield 1776 (Skirmish), Ambush of Geary, Battle of Short Hills, and 72 places are listed on the National Register of Historic Places.

Population by decade

Census Year	Population	Chart
2020	575,345
2010	536,499
2000	522,541
1990	493,819
1980	504,094
1970	543,116
1960	504,255
1950	398,138
1940	328,344
1930	305,209
1920	200,157
1910	140,197
1900	99,353
1890	72,467
1880	55,571
1870	41,859
1860	27,780

Source

Population data from the United States decennial census, U.S. Census Bureau (public domain).

Battles & engagements in Union

Military engagements that took place in Union, New Jersey.

Battle of Springfield 1776 (Skirmish)

1776

Ambush of Geary

1776

Battle of Short Hills

1777

Battle of Spanktown

1777

Battle of Connecticut Farms

1780

Battle of Springfield

1780

Battle of Springfield Jun 23 1780 – Additional detail

1780

Battle of Connecticut Farms (New Jersey)

1780

Battle of Connecticut Farms (1780)

1780

Skirmish at Elizabethtown (1780)

1780

Battle of Springfield New Jersey

1780

Battle of Springfield (1780)

1780

Battle of Spencer's Hill

1780

Battle of Elizabethtown

1780

Battle of Connecticut Farms Jun 7 1780

1780

Skirmish at Elizabethtown Point

1780

Battle of Short Hills (Connecticut Farms)

1780

Battle of Springfield (NJ)

1780

Connecticut Farms Raid (NJ)

1780

Historic places in Union

National Register of Historic Places listings in Union, New Jersey.

North Avenue Commercial District

Plainfield

Plainfield Station

Plainfield

Feltville Historic District

New Providence

Drake, Nathaniel, House

Seventeenth Century Clark House

Liberty Hall (Livingston, Gov. William, House)

Elizabeth

Baltusrol Golf Club

Springfield

Old Baptist Parsonage

Plainfield Civic District

Plainfield

Twin Maples

Summit

Homestead Farm at Oak Ridge

Clark

First Presbyterian Congregation of Connecticut Farms

Union

Belcher-Ogden Mansion-Price, Benjamin-Price-Brittan Houses District

Elizabeth

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Other counties in New Jersey

Explore census history and historic records for more New Jersey counties.

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Everything a full report reveals about Union County, New Jersey

This page charts the census history of Union County, New Jersey. A full Aubrey report for an address here pulls together everything the historical record holds about the ground, from the earliest settlement to the twentieth century:

Overview

An interactive map of the location with historic sites, battles and Native heritage plotted, and its full story era by era.

The Land

The historic sites and place names around the location, and how this land was settled and used.

Geology

The bedrock beneath the site, its age and rock type, reaching back millions of years.

LiDAR Terrain

Laser-scanned terrain that reveals earthworks and old features hidden in the landscape.

Conflict & War

The battles, raids and skirmishes fought near here, across every era of American conflict.

The Civil War

The Civil War on this ground, 1861 to 1865: who held it, and the battles, camps and regiments nearby.

The Soldiers

The men who marched from here in the Civil War, named and traced where the record allows.

Native Heritage

The Native nations who held this land, mapped across time from before European contact to today.

Settlement

Who claimed and held this ground, from Indigenous homelands through the colonial powers to the United States.

The Community

How the town grew, who came, and what kind of place it became, traced through the census record.

Rivers & Rail

The rivers, canals and railroads that connected this place between 1830 and 1911.

Notable People

The people born, buried or genuinely tied to this exact place, with their stories.

Historical Maps

Historic maps of the location layered over how it looks today.

Finds & Access

Museum objects tied to the area, and the laws on searching, collecting and access here.

Literature

The old books, county histories and archives that mention this place, quoted with their sources.

Spotlight

A deep dive into the most remarkable, lesser-known history of the place, traced back to the record.

Points of Interest

The most significant historic sites and landmarks near the location, and why they matter.

Timeline

The whole story of the location told era by era, from first peoples to the present day.

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Frequently asked about Union

When does Union first appear in the US census?

Union, New Jersey first appears in the federal census in 1860, with a recorded population of 27,780.

What is the population of Union?

At the most recent federal census (2020), Union had a recorded population of 575,345.

Were any battles fought in Union?

19 documented military engagements took place in Union, including Battle of Springfield 1776 (Skirmish), Ambush of Geary, Battle of Short Hills.

How many historic places are in Union?

72 sites are listed on the National Register of Historic Places in Union, New Jersey.

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