The Columbia River: Natural Border Between Oregon and Washington

Yes. The Columbia River forms most of the Oregon–Washington state line from its confluence with the Snake River (near the Tri-Cities) westward to the Pacific.

Key facts:

• Length: 1,243 mi (2,000 km)—4th largest U.S. river by volume.
• Source: Columbia Lake, British Columbia.
• Major dams: Bonneville, The Dalles, John Day, McNary, Priest Rapids, Grand Coulee (upstream).
• Economic roles: Hydropower (~40% U.S. total), navigation (barge to Lewiston, ID), salmon fisheries, irrigation.

The river's gorge (Columbia River Gorge) is a National Scenic Area and windsurfing mecca. Its management involves federal, state, tribal, and Canadian agreements.