Lacroix Nunatak () is a ridge of terminal moraine, about 1 nautical mile (1.9 km) long and 75 m high, standing immediately south of a small zone of low rocky ridges which protrude above the ice-covered point 2 nautical miles (3.7 km) southwest of Cape Margerie, Adelie Coast. It was discovered in 1931 by the British Australian New Zealand Antarctic Research Expedition (BANZARE) personnel on the believing it to be a 300-m rock peak. It was named by Mawson after French mineralogist Alfred Lacroix, as was Mount Lacroix. It was photographed from the air by U.S. Navy Operation Highjump, 1946–47, and surveyed by the French Antarctic Expedition, 1949–51, which established an astronomical control station near its center.
This article incorporates public domain material from the United States Geological Survey document "Lacroix Nunatak" (content from the Geographic Names Information System).