Ackerman Nunatak (82°41′S47°45′W) is an isolated nunatak, 655 metres (2,149 ft) high, standing 6.5 miles (10 km) south-southeast of Butler Rocks in northern Forrestal Range, Pensacola Mountains. Mapped by United States Geological Survey (USGS) from surveys and U.S. Navy air photos, 1956–66. Named by Advisory Committee on Antarctic Names (US-ACAN) for Thomas A.