Olallie State Park is a public recreation area featuring multiple waterfalls located five miles (8.0 km) southeast of North Bend, Washington.[2] The state park spans a 3.5-mile (5.6 km) stretch along the South Fork of the Snoqualmie River.[3] The most prominent feature of the park is 135-foot-high (41 m) Twin Falls.[4]
The park originated in 1950, when Washington State Parks purchased a 160-acre parcel from Puget Sound Power and Light. Originally named Twin Falls State Park, following the park's expansion in 1976 its name was changed to Olallie, after a Chinook word for the berries which are common in the park.[2]
The park features old-growth forests and five notable waterfalls: Twin Falls, Middle Twin Falls, Upper Twin Falls, Weeks Falls, and Upper Weeks Falls.
Twin Falls features a well-hidden underground run-of-the-river hydroelectric project that generates 24 MW of electricity.[5] The powerhouse is located 325 feet (99 m) below ground.
Park activities include fishing, hiking, mountain biking, bird watching, and rock climbing.[2] Completed in 2017, the Ollalie Trail added 9.2 miles (14.8 km) of backcountry mountain biking.[6]