The Iowa Army Ammunition Plant (IAAAP) Loads, Assembles, and packs medium- and -large-caliber ammunition items for the Department of Defense using modern production methods in support of world-wide operations.

Iowa Ordnance Plant construction began in January 1941. The plant rolled out its first munitions that September. Production stopped in 1945 when World War II ended.

In 1946, the plant was changed from a Government-Owned, Contractor-Operated facility to a Government-Owned, Government-Operated facility with 277 employees. The mission became ammunition storage, surveillance, munitions demilitarization, facilities renovation and reconditioning. In 1949, the Army resumed ammunition manufacturing for the Korean War. The plant became a GOCO again under Mason & Hangar-Silas Mason Co. in 1951. In 1963, it was re-named the Iowa Army Ammunition Plant. IAAAP increased production during the Vietnam War, and was modernized through the 1970s.

In 1975, the Army designated IAAAP the core plant for warhead and heavy artillery loading with the mission to produce, load, assemble, and pack munitions. Through the Base Realignment and Closure Act of 2005, IAAAP gained several missions from closing ammunition installations, and has actively modernized to support those missions.