Elevation and relief are greatest in the western part of the state and increase somewhat from south to north. The Taconic Mountains, part of the Appalachian system, run along the western border with New York, reaching 2,624 feet (800 meters) at Mount Everett in the state's southwest corner, and including the state's highest point, Mount Greylock, at 3,491 feet (1,064 meters) in the northwest corner. The Housatonic-Hoosic valley separates the Taconics from The Berkshires, a broad belt of steeply rolling hills that are a southern extension of the Green Mountains of Vermont. They extend south to the border of Connecticut. Mount Greylock lies on the western edge of the Taconic Range, across the Hoosic River from the Hoosac Range to the east. The Hoosac Range connects the Green Mountains with the Berkshires.