Multnomah County area

Population and density of Multnomah County

The Census Bureau estimates that 795,391 people lived in Multnomah County on July 1, 2025. That ranks #82 of 3,222 county equivalents nationally and #1 of 36 in Oregon. Since the April 1, 2020 estimates base of 815,400, the population has declined by 20,009 (−2.5%), compared with +0.9% for Oregon as a whole.

With 431 square miles of land, that is 1,845 people per square mile (713 per km²), placing Multnomah County #89 nationally for density and #1 in Oregon. The median county equivalent has 47 people per square mile; the Oregon median is 25. Put another way, there are about 0.347 acres of land per resident.

U.S. Census Bureau, Vintage 2025 population estimates. Estimates are revised each year and are not decennial census counts. Density divides the whole population by the whole county’s land area, so it describes an average, not how settlement is distributed within the county. Population sources and methods.

Cities and towns in Multnomah County

8 incorporated places lie at least partly in Multnomah County. Together they are home to 778,690 people (97.9%); the other 16,701 (2.1%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Portland city, with 632,627 residents in the county (the city extends into 2 other counties). Among places with at least 1,000 residents in 2020, Wood Village city grew fastest since then (+7%).

Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each place inside Multnomah County. Land: 2026 Census Gazetteer, for the whole place even where it extends into other counties. How communities are listed.

Metropolitan area

Multnomah County is a central county of the Portland-Vancouver-Hillsboro, OR-WA Metropolitan Statistical Area. Its 7 county equivalents have 2,542,282 residents on 6,687.4 square miles of land; Multnomah County accounts for 6.4% of the land and 31.3% of the residents. By combined land it ranks #28 of 393 metropolitan areas, and #26 by population. It belongs to the Portland-Vancouver-Salem, OR-WA Combined Statistical Area.

ZIP codes

44 ZIP Code Tabulation Areas have land in Multnomah County; 34 of them have most of their land inside the county, and the others mainly cover neighboring areas.

9700997014970199702497030970349703597056970609708097124971339720197202972039720497205972069720897209972109721197212972139721497215972169721797218972199722097221972229722597227972299723097231972329723397236972399725897266

ZIP Code Tabulation Areas are the Census Bureau’s approximations of USPS ZIP Code service areas, from the 2020 Census relationship files. Lighter codes have less than half of their land in this county. Post-office-box and single-address ZIP Codes have no tabulation area.

Counties bordering Multnomah County

Multnomah County shares a land border with 6 county equivalents, including 2 in Washington. Each of them has more land than Multnomah County. The largest neighbor is Clackamas County (1,870.7 mi²) and the smallest is Hood River County (522.2 mi²). Together with its neighbors, Multnomah County forms a block of 6,493.7 mi² of land, of which it holds 6.6%.

How big is Multnomah County compared with U.S. states?

Multnomah County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 2.4 times as much. Oregon’s county land could hold about 223 areas the size of Multnomah County.

Another way to picture it: the same land area would fill a square about 20.8 miles (33.4 km) on each side. Real county shapes are rarely square, so this is a scale reference rather than a width or driving distance.

State figures are the sums of each state’s county-equivalent land measurements in the same Census release, so states and counties are compared on the same basis. Published state totals can differ slightly because of rounding. Compare all states · Counties bigger than entire states.

What stands out about Multnomah County?

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

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.

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.