Segment of the Pacific Coast Ranges, northwestern Washington, U.S. The mountains extend across the Olympic Peninsula south of the Strait of Juan de Fuca and west of Puget Sound within Olympic National Park .
The chief peaks are Mount Olympus, at 7,965 ft (2,428 m), and Mount Constance, at 7,743 ft (2,360 m). There is heavy rainfall, creating rainforests dominated by Douglas fir and Sitka spruce. Some trees are nearly 300 ft (90 m) high and 8 ft (2.5 m) in diameter.