Olympus Mons to astronomers since the late 19th century as the albedo feature Nix Olympica (Latin for "Olympic Snow"). Its mountainous nature was suspected well before space probes confirmed its identity as a mountain. The volcano is located in Mars's western hemisphere at approximately , just off the northwestern edge of the Tharsis bulge. The western portion of the volcano lies in the Amazonis quadrangle (MC-8) and the central and eastern portions in the adjoining Tharsis quadrangle (MC-9). Two impact craters on Olympus Mons have been assigned provisional names by the International Astronomical Union. They are the -diameter Karzok crater () and
Ascraeus Mons zone of knobby terrain outlined by a semicircular zone of concentric ridges. Similar deposits are also found at the northwestern edges of the other two Tharsis Montes, Pavonis Mons and Arsia Mons, as well as on Olympus Mons. The FSD at Ascraeus Mons is the smallest of those on the Tharsis Montes, covering an area of 14,000 km and extending outward from the volcano's base for about 100 km. The origin of these deposits has been debated for decades. However, recent geologic evidence suggests that FSDs are deposits left by glaciers, which covered portions of the volcanoes during a recent