Aberdeen Proving Ground (APG) is a United States Army facility located near Aberdeen, Maryland. A portion of facility is a census-designated place (CDP). The CDP population at the 2000 census was 3,116.
It is the oldest active proving ground in the country (operational from 1917). In 2005, APG executed an Enhanced use lease (EUL) partnership with Opus East, L.L.C., a commercial real-estate development company. The company in turn gave the EUL to St. John Properties. The latter will now establish commercial office space as well and R&D space on the federally owned property, on a lease.