Oregon Counties by Population (2025)

There are 36 counties in Oregon.

Multnomah County is the largest county in the state, with a population of 779,968. The most recent census shows that its population has decreased by 0.04% since the previous census.

A number of other Oregon counties also boast relatively large populations for their state, though not able to match the density of Multnomah County:

• Washington County : 596,423
• Clackamas County : 423,283

Oregon Counties with the Fewest Residents

The smallest county in Oregon is Wheeler County, with a population of just 1,438. This total represents a decrease of 0.0% since the last census count was performed.

Other small counties include:

• Sherman County : 1,959
• Gilliam County : 2,062
• Grant County : 7,195

Oregon Counties with Rapid Growth

Crook County, with its current population of 28,102, has shown the largest population growth, with an increase of 0.1% since the last census.

Washington County has also had relatively high population growth of -0.01% with 596,423 residents.

On the other hand, Multnomah County has had the largest decrease in population, with its 779,968 current residents totalling 0.0% less than the previous census.