McMurdo Sound and its ice-clogged waters extends about 55 kilometres long and wide. The sound connects the Ross Sea to the north with the Ross Ice Shelf cavity to the south via Haskell Strait. The strait is largely covered by the McMurdo Ice Shelf. The Royal Society Range rises from sea level to 4,205 metres on the western shoreline. Ross Island, an historic jumping-off point for polar explorers, designates the eastern boundary. The active volcano Mount Erebus at 3,794 metres dominates Ross Island. Antarctica's largest scientific base, the United States' McMurdo Station, as well as the New Zealand Scott Base are on the southern shore of the island. Less than 10 percent of McMurdo Sound's shoreline is free of ice. It is the southernmost navigable body of water in the world.
Captain James Clark Ross discovered this sound, which is about 1,300 kilometres from the South Pole, in February 1841, and he named it after Lt. Archibald McMurdo of HMS Terror. The sound today serves as a resupply route for cargo ships and for airplanes that land on the floating ice airstrips near the McMurdo Station.