The Hellas  quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Hellas quadrangle is also referred to as MC-28 (Mars Chart-28). The Hellas quadrangle covers the area from 240° to 300° west longitude and 30° to 65° south latitude on the planet Mars. Within the Hellas quadrangle lies the classic features  Hellas Planitia and Promethei Terra. Many interesting and mysterious features have been discovered in the Hellas quadrangle, including the giant river valleys Dao Vallis, Niger Vallis, Harmakhis, and Reull Vallis—all of which may have contributed water to a lake in the Hellas basin in the distant past. Many places in the Hellas quadrangle show signs of ice in the ground, especially places with glacier-like flow features.