Multnomah County is a county located in the U.S. state of Oregon. As of the 2010 census, the population was 735,334, making it the state's most populous county. The county seat and largest city is Portland. Multnomah County is one of the four counties that make up the Portland metropolitan area. The county was created in 1854 and was named after the Multnomah Indians. Multnomah County provides a wide range of services to its residents, including public health, public safety, and social services. The county is governed by a board of commissioners, which is responsible for setting policy and overseeing the county's operations.