Oregon Counties by Population (2026)

There are 36 counties in Oregon.

Multnomah County is the largest county in the state, with a population of 799,149. The most recent census shows that its population has decreased by 0.02% 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 : 624,154
• Clackamas County : 428,779

Oregon Counties with the Fewest Residents

The smallest county in Oregon is Wheeler County , with a population of just 1,496. This total represents a increase of 0.0% since the last census count was performed.

Other small counties include:

• Gilliam County : 1,843
• Sherman County : 2,098
• Grant County : 6,847

Oregon Counties with Rapid Growth

Crook County , with its current population of 28,088, 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 0.04% with 624,154 residents.

On the other hand, Gilliam County has had the largest decrease in population, with its 1,843 current residents totalling 0.1% less than the previous census.