Tri-Mountain State Park 1 Howd Rd, Durham, CT06422 Tri-Mountain State Park is known for its scenic trails, which include the popular…More 50-mile Mattabesett Trail. Tri-Mountain is 760 (est.) feet above sea level, and its steep traprock terrain provides outstanding views of this section of the Metacomet Ridge, which runs from New Haven to Vermont. A trailhead for the Mattabesset Trail is located at the junction of Route 68 and Route 157. The park is popular with hikers, cross country skiers and snowshoers.