Forest Park is a public municipal park in the Tualatin Mountains west of downtown Portland, Oregon, United States. Stretching for more than on hillsides overlooking the Willamette River, it is one of the country's largest urban forest reserves. The park, a major component of a regional system of parks and trails, covers more than of mostly second-growth forest with a few patches of old growth. About of recreational trails, including the Wildwood Trail segment of the city's 40-Mile Loop system, crisscross the park.