Between 1941 and 1968, the Army Map Service was responsible for the publication and distribution of military topographic maps for use by U.S. military forces. Created from a merger of the Engineer Reproduction Plant and the Army's Geographic Section, the AMS operated under the U.S. Army Corps of Engineers. The mission was to “collect, catalogue, and store foreign and domestic maps and map information required by the War Department; to furnish such map service as required by the General Staff and other authorized agencies; to compile and reproduce maps required for initial operations of field forces; and to develop and improve mapping and map reproduction methods, with particular emphasis upon those most suitable for use in theaters of operation,” according to Army historical documents.

During the balance of World War II, the AMS produced some 500 million topographic maps. The Normandy invasion in June 1944 required nearly 70 million copies of 3,000 different maps. The AMS was later merged into the Defense Mapping Agency – a heritage organization of NGA.