Mikkelsen Bay is a bay, wide at its mouth and indenting , entered between Bertrand Ice Piedmont and Cape Berteaux along the west coast of Graham Land, Antarctica. First seen from a distance in 1909 by the French Antarctic Expedition under Jean-Baptiste Charcot, but not recognized as a large bay. First surveyed in 1936 by the BGLE under Rymill, and resurveyed by the Falkland Islands Dependencies Survey in 1948-49. The name was proposed by members of BGLE for Ejnar Mikkelsen, Danish Arctic explorer and Inspector for East Greenland, 1934-50.