Hertha Nunatak () is a nunatak 1 nautical mile (1.9 km) northwest of Castor Nunatak in the Seal Nunataks group, off the east coast of Antarctic Peninsula. First seen and mapped as an island in December 1893 by Captain C.A. Larsen, who named it after the Hertha, a ship which combined sealing and exploring activities along the west coast of Antarctic Peninsula under Captain C.J. Evensen in 1893-94. It was determined to be a nunatak by the Swedish Antarctic Expedition under Nordenskjold during a sledge journey in 1902.
This article incorporates public domain material from the United States Geological Survey document "Hertha Nunatak" (content from the Geographic Names Information System).