Mount Fitzsimmons is a peak standing between Mounts Jackling and Shideler in the north group of the Rockefeller Mountains

Rockefeller Mountains

The Rockefeller Mountains are a group of low-lying, scattered granite peaks and ridges, almost entirely snow covered, standing 30 miles south-southwest of the Alexandra Mountains on the Edward VII Peninsula of Antarctica....

 on Edward VII Peninsula

Edward VII Peninsula

King Edward VII Land or King Edward VII Peninsula is a large, ice-covered peninsula which forms the northwestern extremity of Marie Byrd Land. The peninsula projects into the Ross Sea between Sulzberger Bay and the northeast corner of the Ross Ice Shelf, and forms part of the Ross Dependency...

. Discovered on January 27, 1929, by members of the Byrd Antarctic Expedition on an exploratory flight to this area. Named for Roy G. Fitzsimmons, physicist in charge of the Rockefeller Mountains seismic station for the United States Antarctic Service (USAS) during November–December 1940.