- Cougar Mountain Regional Wildland Park is a regional park in King County, Washington, near the towns of Bellevue and Issaquah. The park was established in June 1983 to protect the central core of Cougar Mountain, the park covers 3,115 acres (12.61 km2) with 38 miles (61 km) of hiking trails and 12 miles (19 km) of equestrian trails.