Clark Spur is a narrow, rocky spur about 3 nautical miles (6 km) long, extending from the foothills of the Prince Olav Mountains to the edge of the Ross Ice Shelf. The spur forms the eastern side of the mouth of Morris Glacier, about 6 nautical miles (11 km) northwest of Mount Henson. It was discovered and photographed by the Byrd Antarctic Expedition (1928–30) and named for Arnold H.