Multnomah County is one of 36 counties in the U.S. state of Oregon. In 2006, the county's population was 681,454. The county seat is Portland.
History
The county was likely named after Native American people first recorded in the journals of the Lewis and Clark Expedition, Mulknomans, who lived in a village on the east side of present-day Sauvie Island. (An alternative theory holds that Multnomah is a corruption of nematlnomaq, meaning down river.)