Oregon

Union

26,196
2020 population
1870
first census record
16
census records

About Union

Union, Oregon, first appears in the United States federal census in 1870, when it recorded a population of 2,552. At the most recent census, in 2020, its population stood at 26,196.

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

On the ground today, 4 documented military engagements have been recorded within the county, among them Battle of Grande Ronde Valley (Cayuse pursuit), Battle of Grande Ronde Valley, Battle of Birch Creek, and 20 places are listed on the National Register of Historic Places.

Population by decade

Census YearPopulationChart
202026,196
201025,748
200024,530
199023,598
198023,921
197019,377
196018,180
195017,962
194017,399
193017,492
192016,636
191016,191
190016,070
189012,044
18806,650
18702,552
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, Oregon.

Battle of Grande Ronde Valley (Cayuse pursuit)
1848
Battle of Grande Ronde Valley
1866
Battle of Birch Creek
1878
Battle of Birch Creek (Bannock War)
1878

Historic places in Union

National Register of Historic Places listings in Union, Oregon.

Union Main Street Historic District
Union
Eaton, Abel E., House
Union
Hot Lake Resort
La Grande
Administration Building
La Grande
Anthony-Buckley House
La Grande
Ascension Episcopal Church and Rectory
Cove
Browse all Oregonhistoric sites ›

Other counties in Oregon

Explore census history and historic records for more Oregon counties.

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Everything a full report reveals about Union County, Oregon

This page charts the census history of Union County, Oregon. 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, Oregon first appears in the federal census in 1870, with a recorded population of 2,552.
What is the population of Union?
At the most recent federal census (2020), Union had a recorded population of 26,196.
Were any battles fought in Union?
4 documented military engagements took place in Union, including Battle of Grande Ronde Valley (Cayuse pursuit), Battle of Grande Ronde Valley, Battle of Birch Creek.
How many historic places are in Union?
20 sites are listed on the National Register of Historic Places in Union, Oregon.
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