Beacon Hill rises steeply above the surrounding landscape and (est.) above Long Island Sound. It is roughly long by 0.3 miles (0.5 km) wide. The hill lies within the town of Branford. The Farm River runs along the west side of the hill and a tributary salt marsh extends around the south and southeast sides. U.S. 1 borders the hill to the north and separates it from Saltonstall Mountain. A small rock quarry (Johnson's Quarry) abandoned in 1942, occupies the south end of the hill.