Roosevelt Island is the second largest ice rise of Antarctica and world-wide, after Berkner Island. Despite its name, it is not an island, since the bedrock below the ice at its highest part is below sea level. It is about 130 km (81 mi) long in a NW-SE direction, 65 km (40 mi) wide and about 7,500 km (2,896 sq mi) in area, lying under the eastern part of the Ross Ice Shelf of Antarctica. Its central ridge rises to about 550 m (1,804 ft) above sea level, but this and all other elevations of the ice rise are completely covered by ice, so that it is invisible at ground level.
Examination of how the ice flows above it establishes the existence and extent of the ice rise. Radar surveying carried out between 1995 and 2013 showed that the Raymond Effect was operating beneath the ice divide.The ice rise has become a focus of the Roosevelt Island Climate Evolution (RICE) research using ice coring.