Cook Township is a township in Westmoreland County, Pennsylvania, United States. The population was 1,888 at the 2020 census, a decrease from 2,250 at the 2010 census, and 2,403 at the 2000 census.

Linn Run State Park is a Pennsylvania state park on 612 acres (248 ha) 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.