Geography of Washington

Washington State's geography is one of the most dramatic contrasts of any US state — a wet, forested maritime west divided by volcanic mountains from a dry, open eastern landscape.

The Olympic Peninsula occupies the northwestern corner, jutting into the Pacific between the Strait of Juan de Fuca and the Pacific Ocean. The Olympic Mountains rise to over 7,900 feet (Mount Olympus) and intercept Pacific storms, creating the temperate rainforests of the Hoh, Quinault, and Bogachiel river valleys — some of the wettest places in the contiguous US, with over 140 inches of annual rainfall. The Quileute and Hoh peoples have lived here for thousands of years.

Puget Sound is a large inland sea connected to the Pacific Ocean through the Strait of Juan de Fuca. Seattle, Tacoma, Olympia, and Bremerton all sit on the shores of Puget Sound. The sound is over 100 miles long and dotted with islands (Whidbey, Bainbridge, Vashon, and the San Juan Islands, among others).

The Cascade Range runs north-south through the center of the state, forming the primary topographic and climatic divide. Major volcanoes include Mount Rainier (14,411 feet — the highest peak in the state and the most glaciated peak in the contiguous US), Mount Baker, Mount Adams, and Glacier Peak. Mount St. Helens, in the southern Cascades, erupted catastrophically in 1980 — the deadliest and most economically destructive volcanic event in US history.

Eastern Washington is the Columbia Plateau — a vast lava plain covered in dry grassland, wheat fields, and the Channeled Scablands (a dramatic landscape of coulees, lakes, and dry waterfalls carved by catastrophic Ice Age floods from Glacial Lake Missoula). The Yakima Valley is one of the most productive agricultural regions in the US for apples, hops, and wine grapes.

The Columbia River enters Washington from Canada, turns west along the Oregon border, and reaches the Pacific Ocean near Astoria. Grand Coulee Dam on the Columbia — completed in 1942 — is the largest hydroelectric facility in the US.