Aberdeen Proving Ground (Md.)

There are 11 major commands among the tenant units, including

United States Army Communications-Electronics Command (CECOM)

United States Army Combat Capabilities Development Command (CCDC)

United States Army Test and Evaluation Command (ATEC)

Edgewood Arsenal

Adelphi Laboratory Center

The Army Reserve Information Operations Command

Unified Cross Domain Services Management Office

HQ, U.S. Army Contracting Command (Army Contracting Command –APG, Adelphi Contracting Division)

U.S Army 93rd Signal Network - Network Enterprise Center

Logistics Readiness Center

U.S. Army Cyber Operation Group – 335th Signal Command

Blossom Point Research Facility

APG is the U.S. Army's oldest active proving ground, established on 20 October 1917, six months after the U.S. entered World War I. The planning and construction were overseen by Brigadier General Colden Ruggles, who later served as the Army's Chief of Ordnance. Its location allowed design and testing of ordnance materiel to take place near contemporary industrial and shipping centers. The proving ground was created as a successor to the Sandy Hook Proving Ground, which was too small for some of the larger weapons being tested. At the peak of World War II, APG had billeting space for 2,348 officers and 24,189 enlisted personnel.

Aberdeen was home to the Army Pulse Radiation Facility Reactor, in 1968. On 6 September 1968, this reactor was the site of a prompt critical excursion during commissioning tests. This accident harmed no personnel but did release enough heat to reach the melting point of the fuel in the core, 1150°C. This caused damage to the fuel components of the reactor, fusing the four central rings together. This is one of thirty-three prompt critical accidents worldwide, between 1949 and 2000.