Mount Walnum () is a large mountain rising to 2,870 m, standing 4 nautical miles (7 km) east of Mount Wideroe in the Sor Rondane Mountains. Mapped by Norwegian cartographers in 1946 from air photos taken by the Lars Christensen Expedition 1936-37 and named for Ragnvald Walnum, one-time chairman of the Norwegian Whaling Board, who prepared an ice chart of Antarctica. Remapped by the Norwegians in 1957 from air photos taken by U.S. Navy Operation Highjump, 1946-47.
This article incorporates public domain material from the United States Geological Survey document "Mount Walnum" (content from the Geographic Names Information System).