Mount Washington State Forest is a 4,619-acre protected area in the southern Taconic Mountains of southwestern Massachusetts, bordering both New York and Connecticut beside Bash Bish Falls State Park. Given to the state in stages between 1958 and 1968 by Alfred F. Intemann and Cornelia Van der Smissen Intemann, it preserves a mountainous public landscape valued for scenery and recreation. Its notable features include 300 acres of old-growth northern hardwood forest and the tri-state boundary stone on the Mount Frissell Trail, marking Massachusetts’s southwestern corner. About 30 miles of trails, including parts of the Appalachian and South Taconic trails, support a wide range of outdoor activities.