The Multnomah Channel is a 21.5-mile (34.6 km) distributary of the Willamette River. It diverges from the main stem a few miles upstream of the main stem's confluence with the Columbia River in Multnomah County in the U.S. state of Oregon. The channel flows northwest then north around Sauvie Island to meet the Columbia River near the city of St. Helens, in Columbia County.