Hot springs in Washington

Most of Washington's thermal springs lie near or just west of the crest of the Cascade Range, and many are tied to the large stratovolcanoes of the Cascade arc. A U.S. Geological Survey study of the state's thermal waters and a later Washington Geological Survey summary both describe this pattern. The Washington Geological Survey, part of the Department of Natural Resources, notes that the state has no geothermal power plants, but that elevated crustal heat near the Cascade volcanoes points to resources around Mount Baker, Mount St. Helens and the Wind River valley. A smaller group of springs lies in the Olympic Mountains.

Public land around these springs is managed mainly by three national forests and one national park. The Mount Baker-Snoqualmie National Forest covers the west slope from the Canadian border to the Mount Rainier area, the Gifford Pinchot National Forest covers the south Cascades and the Wind River valley, and the Okanogan-Wenatchee National Forest covers the east slope. Olympic National Park manages the springs in the Elwha valley. Several of the state's better-known springs are developed private or concession properties.

Snow controls access for much of the year. In Olympic National Park, the Olympic Hot Springs Road has been closed to vehicles beyond the Madison Falls area since flood damage in the Elwha valley, and the park lists the road as open to pedestrians and bicycles. The Washington State Department of Transportation closes the North Cascades Highway, State Route 20, between the Ross Dam trailhead and the Silver Star gate, usually in November, and reopens it in late April or May. Chinook Pass on State Route 410 and Cayuse Pass on State Route 123 typically close from mid-November to late May.