Mendip Hills, range of hills, c.25 mi (40 km) long, across N Somerset, SW England, extending SE from the vicinity of Hutton to the Frome valley. Primarily limestone, the hills have numerous caves (Wookey Hole, Cheddar Caves), some of which show signs of prehistoric occupation. In the hills are ruins of Roman lead mines, an amphitheater, and a Roman road. The gorges near Cheddar are particularly notable. Livestock raising and quarrying are important there.