An isolated group of mountains in West Antarctica, consisting of three mountains and a cluster of nunataks extending over 15 miles. The group was visited and surveyed on Jan. 2, 1959, by William H. Chapman, cartographer with the Horlick Mountains Traverse Party (1958-59). Named by Chapman for George D. Whitmore, Chief Topographic Engineer, USGS, who was a member of the Working Group on Cartography of the Scientific Committee on Antarctic Research.