Linn Run State Park is a Pennsylvania state park on 612 acres in Cook and Ligonier Townships, Westmoreland County, Pennsylvania in the United States. The park borders Forbes State Forest. Two smaller streams, Grove Run and Rock Run, join in Linn Run State Park to form Linn Run which has a waterfall, Adams Falls, which can be seen at the park. This state park is just off Pennsylvania Route 381 near the small town of Rector.