County · code 41061
Union CountyOregon
Union County is a county in northeastern Oregon, with its seat in La Grande, formed in 1864.
- Founded1864
- County seatLa Grande
- Named forUnion, Oregon
- Land area2,037 sq mi + 1.9 sq mi water
- Population26,196 2020 Census
Where it is
Union on the map of Oregon
Oregon has 36 counties and county equivalents, each with its own records office. Shapes with a page are links.
History
Formed in 1864 from Baker County and Grant County
An old deed may name a county that no longer exists, or a boundary that has since moved.
Union County was created on October 14, 1864, from Baker and Grant Counties. The county's boundaries shifted several times over the next 50 years through exchanges and transfers with neighboring Baker, Grant, Wallowa, and Umatilla Counties.
- 1864Union County created Union created from Baker. Southwest portion of Union overlapped the northeast corner of Grant (see Overlap Area). · Ore. Laws 1864, 3rd reg. sess., p. 37
- 1878Gained territory Union gained area of overlap from Grant, lost to Baker. · Ore. Special Laws 1878, 10th reg. sess., pp. 118-120
- 1887Lost territory Union lost to creation of Wallowa. · Ore. Laws 1887, gen., 14th reg. sess., pp. 142-145
- 1899
- 1901
Show all 11 changes
- 1864Union County created Union created from Baker. Southwest portion of Union overlapped the northeast corner of Grant (see Overlap Area). · Ore. Laws 1864, 3rd reg. sess., p. 37
- 1870Boundary clarified Area of overlap between Union and Grant was reduced when Grant boundaries were redefined.with Grantno change· Ore. Laws 1870, 6th reg. sess., pp. 167-168
- 1872Boundary clarified Area of overlap between Union and Grant was increased when Grant boundaries were redefined.with Grantno change· Ore. Laws 1872, 7th reg. sess., pp. 34-35
- 1874Changed In an effort to resolve boundary conflicts between Baker, Grant, and Union the legislature passed "An Act to Create a Commission from Grant and Baker Counties, to establish an Initial Point to define the Boundary Line between Grant and Baker Counties, and to Create a Commission from Baker and Union Counties to designate by Name which Fork of the North Fork of Powder River shall be the line between Baker and Union Counties." · Ore. Laws 1874, 8th reg. sess., pp. 91-92
- 1878Gained territory Union gained area of overlap from Grant, lost to Baker. · Ore. Special Laws 1878, 10th reg. sess., pp. 118-120
- 1887Lost territory Union lost to creation of Wallowa. · Ore. Laws 1887, gen., 14th reg. sess., pp. 142-145
- 1899
- 1901
- 1907Exchanged territory Union exchanged with Umatilla. Two mistakes in the line as described were corrected on 27 February 1913. · Ore. Laws 1907, gen., 24th reg. sess., ch. 20/pp. 29-31
- 1913Boundary clarified Union boundary Wallowa redefined to correct two mistakes in the boundary description of 13 February 1907 (no change).with Wallowano change· Ore. Laws 1913, gen., 27th reg. sess., ch. 309/pp. 598-600
- 1915Exchanged territory Union exchanged with Wallowa. · Ore. Laws 1915, gen., 28th reg. sess., ch. 134/pp. 145-146
Land and parcels
What the maps cover in Union
Who publishes each layer, how good it is, and when we last checked.
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Parcels Missing
No public parcel map found for Union County yet. Lot lines and owners of record are kept by the county (union-county.org).
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Address points Official
One point per address, 11,700 in all from State of Oregon — Department of Administrative Services Geospatial Enterprise Office (GEOHub) with Oregon Department of Emergency Management 9-1-1 program.
edited 16 January 2026 · checked 13 October 2026 -
Buildings Reference
Roof outlines traced from aerial imagery from FEMA Response Geospatial Office with Oak Ridge National Laboratory (ORNL). Good for seeing what is on a lot; not accurate enough to set a fence from.
checked 18 October 2026
- Official
- from the office that keeps the record
- Good enough
- a reliable statewide or national copy
- Fallback
- a guide only; check the official record
- Missing
- nothing public found yet
People and land
Union by the Census
Source: US Census Bureau, 2020 Census; US Census Bureau, 2020 Gazetteer Files. Not endorsed or certified by the Census Bureau.
Rules and offices
Who to ask before you build, dig or sell
Official county pages only. We link to them; we do not copy them, because they change.
Inside a city or town, permits usually come from that city rather than the county.
Permits
County government
- County government
The official website of Union County.
See your own lot on these maps
Open Union County on Parcel Chart's free map and click your parcel. Save it with a free account; the full record of your place (site map, projects, documents) is Pro, in early access.
Questions
Common questions about Union County
- When was Union County founded?
- Union County was founded in 1864, formed from Baker County and Grant County, and named after Union, Oregon.
- What is the county seat of Union County?
- The county seat of Union County is La Grande.
- Is there an online parcel map for Union County?
- Not that we have found yet. Lot lines and owners of record are kept by the county assessor's office. When a public parcel map appears, it shows here.
- Has Union County's boundary or name changed?
- Union County was created in 1864 from Baker County and Grant County. Since then the Atlas of Historical County Boundaries records 7 later changes, chiefly involving Baker County, Wallowa County and Grant County.
- Who issues building permits in Union County?
- The county's page on building permits: Building Permit. Inside a city or town, ask that city first.
- Is my lot in a flood zone?
- We do not have flood maps for Union County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.
Nearby