Mount Erebus is the second-highest volcano in Antarctica, the highest active volcano in Antarctica, and the southernmost active volcano on Earth. It is the sixth-highest peak of an island and the second most prominent mountain in Antarctica after Mount Vinson. It has a summit elevation of 3,794 metres (12,448 ft). It is located in the Ross Dependency on Ross Island, which is also home to three inactive volcanoes: Mount Terror, Mount Bird, and Mount Terra Nova. The mountain was named by Captain James Clark Ross in 1841 for his ship, the Erebus.

The Ross Dependency is a region of Antarctica defined by a sector originating at the South Pole, passing along longitudes 160° east to 150° west, and terminating at latitude 60° south. It is claimed by New Zealand, a claim accepted by the other six countries with territorial claims in Antarctica. Under the 1961 Antarctic Treaty, of which all territorial claimants are signatories, including New Zealand, all claims are held in abeyance. Article IV states: "No acts or activities taking place while the present Treaty is in force shall constitute a basis for asserting, supporting or denying a claim to territorial sovereignty in Antarctica or create any rights of sovereignty in Antarctica".