Fanno Creek is a 15-mile (24 km) tributary of the Tualatin River in the U.S. state of Oregon.[3] Part of the drainage basin of the Columbia River, its watershed covers about 32 square miles (83 km2) in Multnomah, Washington, and Clackamas counties, including about 7 square miles (18 km2) within the Portland city limits.
From its headwaters in the Tualatin Mountains (West Hills) in southwest Portland, the creek flows generally west and south through the cities of Portland, Beaverton, Tigard and Durham, and unincorporated areas of Washington County. It enters the Tualatin River about 9 miles (14 km) above the Tualatin's confluence with the Willamette River at West Linn.
From its headwaters in the Tualatin Mountains (West Hills) in southwest Portland, the creek flows generally west and south through the cities of Portland, Beaverton, Tigard and Durham, and unincorporated areas of Washington County. It enters the Tualatin River about 9 miles (14 km) above the Tualatin's confluence with the Willamette River at West Linn.