High Quality Content by WIKIPEDIA articles! Forest Park is a public municipal park in the Tualatin Mountains west of downtown Portland, Oregon, United States. Stretching for more than 8 miles (13 km) 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 5,100 acres (2,064 ha) of mostly second-growth forest with a few patches of old growth. About 70 miles (110 km) of recreational trails, including the Wildwood Trail segment of the city`s 40 Mile Loop system, crisscross the park.