During WWII the United States Army and Army Air Force grew from a domestic force of 1,400,000 personnel in 1941 into a global force of over 8,300,000 by 1945. Correspondingly this WWII U.S. Military Grouping contains flags from the period; indulging national flags, unit colors, corps flags, guidons and ephemera.

Perhaps the most poignant artifact in the WWII Military Grouping is the co-pilots log from the B-29 Enola Gay, for August 6, 1945, annotated by Captain Paul Lewis, USAAF, who notably recorded on page 9 "My God what have we done."

Hiroshima associated artifacts are the "omega"of U.S. World War II collectibles. (NB: Please see the following Grouping for the "alpha" of U.S. WWII collectibles, a 48 star U.S. flag recovered from the sunken USS Arizona (BB-39).

Of interest in the Grouping are artifacts and flags pertaining to some of the most famous military operation of the conflict; Operation Torch, D-Day, the Battle of the Bulge, the Central Europe Campaign and the Invasion of Germany as well as the Air war over Germany and Japan.