On a background equally divided horizontally white and red, 3 1/4 inches in height and 2 1/2 inches in width at base and 2 1/8 inches in width at top, a black block letter "A", 2 3/4 inches in height, 2 inches in width at base and 1 5/8 inches in width at top, all members 7/16 inch wide, all enclosed within a 1/8 inch Army Green border.
The red and white of the background are the colors used in flags for Armies. The letter "A" represents "Army" and is also the first letter of the alphabet suggesting "First Army."
A black letter "A" was approved as the authorized insignia by the Commanding General, American Expedition Force, on November 16, 1918 and approved by the War Department on May 27, 1922. The background was added on November 17, 1950. (TIOH Drawing Number A-1-1)