Peak Mountain, also called Copper Mountain, est. 730 feet (220 m), is a traprock mountain located in East Granby, Connecticut, 6 miles (10 km) south of the Massachusetts border and 6 miles west of the Connecticut River. It is part of the narrow, linear Metacomet Ridge that extends from Long Island Sound near New Haven, Connecticut, north through the Connecticut River Valley of Massachusetts to the Vermont border. Peak Mountain is known for its expansive views from 200 feet (61 m) high cliffs overlooking the historic Old Newgate Prison, Congamond Lake, and the Salmon Brook Valley of north-central Connecticut. The mountain is also known for its microclimate ecosystems, rare plant communities, and as a seasonal raptor migration path.