Multnomah County /mʌltˈnoʊmə/ is one of 36 counties in the U.S. state of Oregon. As of the 2020 United States Census, the county's population was 815,428. Its county seat, Portland, is the state's largest city.
Multnomah County is part of the Portland-Vancouver-Hillsboro, OR-WA Metropolitan Statistical Area. It is the state's most populous county.