Foundation Ice Stream is a major ice stream in Antarctica's Pensacola Mountains. The ice stream drains northward for 150 miles (240 km) along the west side of the Patuxent Range and the Neptune Range to enter the Ronne Ice Shelf westward of Dufek Massif. The United States Geological Survey mapped the stream from surveys and U.S. Navy air photos, 1956–66. The Advisory Committee on Antarctic Names named the stream in recognition of the National Science Foundation, which provided major support to the U.S.