Marine Corps Base Quantico (commonly abbreviated MCB Quantico) is a United States Marine Corps installation located near Triangle, Virginia, covering nearly 55,148 acres (86.169 sq mi) of southern Prince William County, Virginia, northern Stafford County, and southeastern Fauquier County. Used primarily for training purposes, MCB Quantico is known as the "Crossroads of the Marine Corps". Quantico Station is a census-designated place (CDP) in Prince William and Stafford counties in the U.S. state of Virginia, used by the Census Bureau to describe base housing. The population was 4,452 at the 2010 census. The U.S. Marine Corps' Combat Development Command, which develops strategies for U.S. Marine combat and makes up most of the community of over 12,000 military and civilian personnel (including families), is based here. It has a budget of around $300 million and is the home of the Marine Corps Officer Candidates School. The Marine Corps Research Center at Quantico pursues equipment research and development, especially telecommunications, for the Marine Corps. The Marine Corps Brig, a military prison, was also located at Quantico, until its closure on 31 December 2011 and its subsequent demolition. The FBI Academy, the principal research and training facility of the Federal Bureau of Investigation, and the principal training facility for the Drug Enforcement Administration (DEA) are also located on the base. In 2001, the base was designated as part of the Quantico Marine Corps Base Historic District by the National Register of Historic Places. This district includes 122 buildings, two landscapes, a sculpture, and a water tower located within the Mainside area of the base. The contributing properties with separate entries include Tennessee Camp, Camp French, Commanding General's Quarters, and Rising Hill Camp.