Harrison Hills Park is a five hundred-acre regional county park in Harrison Township, Allegheny County, Pennsylvania, northeast of Pittsburgh. Part of Allegheny County’s nine-park system, it is known for its elevated setting above the Allegheny River, with an overlook offering wide views of the river valley. The park includes walking, hiking, and bridle trails, and its Environmental Learning Center is open on weekends. It also serves as the eastern trailhead of the Rachel Carson Trail, whose route along the park’s eastern bluff crosses Rachel Carson Run on a wooden arch bridge above Rachel Carson Falls. In early 2016, a beaver at South Pound helped clear non-native Russian olive trees along the shore.