THE MULTNOMAH COUNTY LAND BRIEF
Land in the
Portland/Vancouver Basin setting.
Multnomah County has 431 square miles of land in Oregon. 7 mapped landscape regions meet across Multnomah County: Portland/Vancouver Basin, Western Cascades Lowlands and Valleys, Valley Foothills, among others.
The Willamette River's floodplains and terraces sit among low hills and scattered buttes. The valley's prairie, oak and riparian landscape differs markedly from the conifer-covered mountains around it.
Regional context: Willamette Valley ↗ · Regional mapping across the county footprint
Where the landscape changes
Multnomah County intersects 7 mapped regional units. The largest mapped shares are:
- Portland/Vancouver Basin40.2%
- Western Cascades Lowlands and Valleys28.9%
- Valley Foothills13.6%
- Western Cascades Montane Highlands9.4%
- Volcanics6.4%
Cascades in Multnomah County
Volcanic mountains, deeply cut stream valleys and glaciated high country define the Cascades. Conifer forests change with elevation, giving way to mountain meadows and rocky alpine terrain.
Read the regional source ↗Coast Range in Multnomah County
Pacific-facing coastal mountains support moisture-loving conifers, with marine terraces, dunes and beaches along the ocean edge. Inland slopes and the immediate coast have different vegetation patterns.
Read the regional source ↗Finding your parcel within Multnomah County
The atlas lists 12 cities, towns, townships, and Census communities associated with Multnomah County, including Portland, Gresham, Lake Oswego. The list includes overlapping geography types and does not divide the county into exclusive service areas.
Multnomah County by land and water
The Census records 34 square miles of water within Multnomah County, or 7.3% of its total area. That share is close to Multnomah County’s 7.3%. This is geographic context; waterfront status and usable land must be checked at the parcel.
For scale, Multnomah County has 457.5 times the land area of nearby Wood Village city (0.94 square miles). These areas describe boundaries, not comparable property prices.
The Census boundary meets Clackamas County, Columbia County, Hood River County, Washington County within Oregon. A tract near one of these lines should be matched to the county identifier on its own records.

