Officially, the area is designated by the U.S. Office of Management and Budget (OMB) as the Washington-Baltimore-Northern Virginia, DC-MD-VA-WV Combined Statistical Area (CSA). The CSA is composed primarily of two major metropolitan areas, the Baltimore-Towson Metropolitan Statistical Area (MSA) and the Washington-Arlington-Alexandria, DC-VA-MD-WV MSA. In addition, three other smaller urban areas not contiguous to the main urban area but having strong commuting ties with the main area are also included in the metropolitan area. These are the Winchester, VA-WV MSA, the Lexington Park, MD Micropolitan area and the Culpeper, VA Micropolitan area. Some counties and cities are not officially designated by the OMB as members of this metropolitan area, but still consider themselves members anyway. This is mostly due to their proximity to the area, the size of their commuter population, and by the influence of local broadcasting stations. The population of the entire Baltimore-Washington Metroplex as of 2004 is 8,026,807. The most populated city is Baltimore, with a population of just above 640,000 people. The most populated county is Fairfax County, with over 1,000,000 people.
