New Mexico

Union

4,079
2020 population
1900
first census record
13
census records

About Union

Union, New Mexico, first appears in the United States federal census in 1900, when it recorded a population of 4,528. At the most recent census, in 2020, its population stood at 4,079.

Its recorded population peaked at 16,680 in 1920, and has since declined by roughly 76 percent.

On the ground today, one documented military engagement has been recorded within the county, among them Black Jack Ketchum Train Robbery, and 11 places are listed on the National Register of Historic Places.

Population by decade

Census YearPopulationChart
20204,079
20104,549
20004,174
19904,124
19804,725
19704,925
19606,068
19507,372
19409,095
193011,036
192016,680
191011,404
19004,528
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 Mexico.

Black Jack Ketchum Train Robbery
1899

Historic places in Union

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

Goodson Memorial School
Seneca
Amistad Gymnasium
Amistad
Rabbit Ears
Clayton
Clayton Public Library
Clayton
Gate, Fence and Hollow Tree Shelter Designed by Dionicio Rodriguez
Clayton
Folsom Hotel
Folsom
Clayton Public Schools Historic District
Clayton
Luna Theater
Clayton
Browse all New Mexicohistoric sites ›

Other counties in New Mexico

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

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Everything a full report reveals about Union County, New Mexico

This page charts the census history of Union County, New Mexico. 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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New Mexicohistory ›NRHP historic sites ›Notable people from New Mexico›

Frequently asked about Union

When does Union first appear in the US census?
Union, New Mexico first appears in the federal census in 1900, with a recorded population of 4,528.
What is the population of Union?
At the most recent federal census (2020), Union had a recorded population of 4,079.
When did Union's population peak?
Union's recorded population peaked at 16,680 in 1920.
Were any battles fought in Union?
1 documented military engagement took place in Union, including Black Jack Ketchum Train Robbery.
How many historic places are in Union?
11 sites are listed on the National Register of Historic Places in Union, New Mexico.
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