Columbia River Facts

 Columbia = the Great River of the West

The Watershed

At over 1,200 miles in length, the Columbia River is the lifeblood of the Pacific Northwest and one the most important rivers in the world. It is the fourth largest river by volume in North America, draining an area the size of France (259,000 square miles). The Columbia River watershed extends from the Canadian Rockies in British Columbia to the Pacific Ocean near Astoria, Oregon. It drains portions of seven states and British Columbia.


Major Tributaries

The Columbia River’s major tributaries are the Kootenai, the Pend Oreille/Clark’s Fork/Flathead, Spokane, Okanogan, Methow, Yakima, Snake, Umatilla, John Day, Deschutes, White Salmon, Wind, Sandy, Willamette, Lewis and the Cowlitz Rivers. Its largest tributary, the Snake River, travels 1,083 miles from its source in Yellowstone National Park in Wyoming to meet with the Columbia near the Tri-cities in Eastern Washington.


Formation & Floods

The physical characteristics of the modern Columbia River basin formed between 12,000 and 19,000 years ago at the end of the last ice age. Massive ice dams held back melting ice creating a huge lake in northwest Montana, called Lake Missoula. Repeatedly the ice dam gave way, releasing towering walls of water that rushed seaward, generally following the route of the present day Columbia River. These floods are responsible for the dramatic landscape of the Columbia River Gorge and the channeled scablands of the Columbia Basin.


ODFWSalmon & Steelhead in the Columbia

The Columbia River supported one of the greatest salmon and steelhead runs on Earth. Prior to the 1840’s, up to 16 million salmon and steelhead returned to the Columbia River to spawn each year. Unfortunately, throughout the 20th century that number has declined to less than 1 million fish per year. The Columbia’s famous salmon runs, along with other fish and wildlife populations, historically supported, and continue to sustain, rich Native American cultures and traditions across the Columbia River Basin. Powerful images depicting the rich diversity of the Columbia’s fish and wildlife are etched and painted onto basalt rocks throughout the Columbia Basin. The Columbia River salmon fishery supports thousands of commercials fishermen, fishing guides, and gear manufacturers both on the river and along the Pacific Coast.


Endangered Species

In response to the severe population declines of Columbia River salmon, in the 1990s the National Marine Fisheries Service (NMFS) designated thirteen stocks of anadromous salmonids as Threatened or Endangered with extinction under the Endangered Species Act (ESA). The ESA protects species and critical habitat to prevent extinction. More recently, dams, poor water quality, and habitat destruction also caused bull trout, green sturgeon, and eulachon (smelt) to join the list of species threatened with extinction in June of 2010. Our government continues to add Columbia River species to the ESA, but have not taken strong enough action to remove them from the threatened status.



The Columbia River is one of the world’s largest hydropower systems. There are fourteen dams on the mainstem of the Columbia River and over 450 dams throughout the entire Columbia Basin. The dams on the Columbia River and its tributaries produce half of the electricity consumed in the Pacific Northwest. These dams significantly alter the river’s flow, water quality, and salmon runs. Logging, water diversions for agriculture, and human population growth have also altered the Columbia’s flow regime and water quality, reducing the quality of salmon habitat across the river basin. The Columbia River’s water quality, and in-turn, the health of fish, animals, and people that rely on the Columbia, is also degraded by industrial and municipal pollution, toxic waste dumps, including the Hanford Nuclear Reservation, and pesticide and fertilizer runoff.