Defant Glacier is a glacier 2 nautical miles (4 km) wide at its mouth, which flows east-southeast to the west side of Violante Inlet, on the east coast of Palmer Land. It was discovered and photographed from the air in December 1940 by the United States Antarctic Service; during 1947 the glacier was photographed from the air by members of the Ronne Antarctic Research Expedition, who in conjunction with the Falkland Islands Dependencies Survey (FIDS) charted it from the ground.