THE MORROW COUNTY LAND BRIEF
Land in the
Umatilla Plateau setting.
Morrow County has 2,030.5 square miles of land in Oregon. 8 mapped landscape regions meet across Morrow County: Umatilla Plateau, Pleistocene Lake Basins, Umatilla Dissected Uplands, among others.
Basalt underlies this dry plateau of grassland and sagebrush. Windblown soils cover some uplands, while ancient flood paths exposed rock across the region's scabland terrain.
Regional context: Columbia Plateau ↗ · Regional mapping across the county footprint
Where the landscape changes
Morrow County intersects 8 mapped regional units. The largest mapped shares are:
- Umatilla Plateau44.9%
- Pleistocene Lake Basins24.2%
- Umatilla Dissected Uplands11.2%
- Maritime-Influenced Zone7.7%
- John Day/Clarno Highlands7.6%
Blue Mountains in Morrow County
The Blue Mountains combine open mountain ranges and dissected volcanic uplands. The Wallowa and Elkhorn high country includes older granitic and metamorphic rocks above the surrounding lava landscape.
Read the regional source ↗Finding your parcel within Morrow County
The atlas lists 5 cities, towns, townships, and Census communities associated with Morrow County, including Boardman, Irrigon, Heppner. The list includes overlapping geography types and does not divide the county into exclusive service areas.
Morrow County by land and water
The Census records 17.1 square miles of water within Morrow County, or 0.8% of its total area. That share is close to Morrow County’s 0.8%. This is geographic context; waterfront status and usable land must be checked at the parcel.
For scale, Morrow County has 4,646.5 times the land area of nearby Lexington town (0.44 square miles). These areas describe boundaries, not comparable property prices.
The Census boundary meets Gilliam County, Grant County, Umatilla County, Wheeler County within Oregon. A tract near one of these lines should be matched to the county identifier on its own records.

