OR · GEOID 41051

Multnomah County area

Multnomah County, Oregon covers 465 square miles: 431 square miles of land and 34 square miles of water.

Official Census measurements2026 Gazetteer · retrieved September 27, 2026
Land area431 mi²
Water area34 mi²
Total area465 mi²
National land rank#2359

County outline

Generalized outline of Multnomah County, Oregon
2025 Census cartographic boundary, fitted to this frame. County maps are not at a common scale. The 2026 area measurements below come from the separate Gazetteer release. Map source and limitations.

Where Multnomah County is located

Multnomah County highlighted on a map of all U.S. county equivalents. About the maps

Area breakdown

Land accounts for 92.7% of Multnomah County’s measured area and water for 7.3%. Its combined area converts to 1,204.4 square kilometers or approximately 297,606 acres.

Green: land · blue: water

MeasurementSquare milesSquare kilometersAcres
Land431.0131,116.319275,848.3
Water33.99688.04921,757.4
Total465.0091,204.368297,605.8

How Multnomah County compares

By original Census land area, Multnomah County ranks #36 of 36 in Oregon and #2359 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.

Its land area is 0.236 times the Oregon county-equivalent median of 1,826.2 square miles. It accounts for 0.4% of the combined county land area in the state.

See the complete Oregon ranking · What counts as a county equivalent?

What stands out about Multnomah County?

Multnomah County has more land than 863 of the other 3,221 county equivalents in the dataset.

Land area compared with the typical county equivalent
Multnomah County431 mi²
Oregon median1,826.2 mi²
National median604.5 mi²

A median is the middle county-equivalent measurement, not the average of the largest and smallest. All three bars use the same linear scale. Very small areas may appear as a thin sliver; the labels retain their values.

Does including water change its rank?

Using land plus water places Multnomah County at #2,303 nationally by total area, 56 places closer to the top than its land rank. The water assigned to this geography moves it ahead of some county equivalents with more land.

Its water share is 7.3%, compared with a national county-equivalent median of 1.2% — 6.1 percentage points higher. This describes the statistical geography’s land/water mix, not flood exposure or developable land.

Closest positions in the national land ranking

These entries sit immediately beside Multnomah County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Land rankCounty equivalentLand mi²Comparison
#2358Pawnee County, Nebraska431.1Compare
#2359Multnomah County, Oregon431This county
#2360Westchester County, New York430.8Compare

Calculated from the same Census release as the area table. Total-area order uses original ALAND + AWATER; water shares and chart labels use published square miles. Calculation details.

Representative coordinates

The Census internal point is 45.547168, -122.414003. It represents a location inside the geography; it is not necessarily the centroid or the address of a courthouse.

Source and precision

U.S. Census Bureau, 2026 Gazetteer Files, Counties. Original ALAND: 1,116,317,985 m²; AWATER: 88,048,650 m². Rankings use ALAND; exact ties use ascending GEOID. Tables preserve Census-published square miles to three decimals, with conversions based on those values.

Download the official county source ZIP ↗ · Methodology

Common questions

How many acres of land are in Multnomah County?

The land measurement converts to approximately 275,848 acres. Including water, total area is approximately 297,606 acres. One square mile equals 640 acres.

Why might another source show a different area?

Check whether it reports land or total area, its Census vintage, and its rounding. Our guide explains how to reconcile county area figures.

Can this establish a property boundary?

No. Statistical measurements and generalized maps do not establish property lines. Consult the relevant local surveying or land-records authority.

Cite this county

Download the complete CSV or JSON dataset