The Alley Spur (82°32′S51°47′W) is a rock spur on the north side of the Dufek Massif, just south of Sapp Rocks, in the Pensacola Mountains of Antarctica. It was mapped by the United States Geological Survey from surveys and U.S. Navy air photos, 1956–66, and named by the Advisory Committee on Antarctic Names for Captain Dalton E.