Despite its name, it is not an island, since the bedrock below the ice at its highest part is below sea level.

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.

[1] [2] Radar surveying carried out between 1995 and 2013 showed that the Raymond Effect was operating beneath the ice divide.

[5] Rear Admiral Richard E. Byrd named it in 1934 after US President Franklin D. Roosevelt.

[6] Roosevelt Island lies within the boundaries of the Ross Dependency, New Zealand's Antarctic claim.