Trimountain or Tri-mountain, est. , is a traprock mountain located southeast of Meriden, Connecticut. 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. Trimountain is known for its scenic cliff faces, unique microclimate ecosystems, and rare plant communities. The mountain is traversed by the Mattabesett Trail.