Nilsen Island (54°39′S 36°25′W / 54.650°S 36.417°W) is a small island lying 1.5 nautical miles (2.8 km) west of the north part of Novosilski Bay, off the south coast of South Georgia. The island has appeared on charts since the 1930s. It was recharted by SGS in the period 1951–57, and named by the United Kingdom Antarctic Place-Names Committee (UK-APC) for , gunner of the de Pesca, Grytviken, 1939–40 and 1946–48, and of the , Leith Harbor, for several years beginning in 1949.