Cape Sheffield is a cape forming the northwest extremity of Rugged Island in the South Shetland Islands, Antarctica. It was named for Captain James P. Sheffield, Master of the brig Hersilia of Stonington, Connecticut, in 1819–20 and 1820–21, the first American sealer known to have visited the South Shetland Islands. In 1819–20 he took 8,868 sealskins from headquarters at Rugged Island.