The Mayer Crags (84°53′S 168°45′W) form a rugged V-shaped massif in Antarctica. The feature is 10 nautical miles (19 km) long, surmounted by several sharp peaks, and located at the west side of the mouth of Liv Glacier, where the latter enters the Ross Ice Shelf. It was named by the Advisory Committee on Antarctic Names for Lieutenant Robert V. Mayer, U.S. Navy, a pilot of Hercules aircraft in four Antarctic seasons, and plane commander for a mid-winter evacuation flight on June 26, 1964.
The highest peak of the Mayer Crags is Mount Koob, at 1,600 metres (5,250 ft). It stands 4 nautical miles (7 km) northwest of Mount Ferguson and was named by the Advisory Committee on Antarctic Names for Derry D. Koob, a United States Antarctic Research Program biologist at McMurdo Station in the 1964–65 and 1965–66 seasons.