Northern Virginia – commonly referred to as NOVA – comprises several counties and independent cities in the Commonwealth of Virginia, in a widespread region generally radiating southerly and westward from Washington, D.C. With 2.8 million residents (about a third of the state), it is the most populous region of Virginia and the Washington metropolitan area.
Communities in the region form the Virginia portion of the Washington metropolitan area and the larger Baltimore-Washington metropolitan area. Northern Virginia has a significantly larger job base than either Washington or the Maryland portion of its suburbs,and is the highest-income region of Virginia, having seven of the 20 highest-income counties in the nation, including the three highest as of 2009[update].
Northern Virginia's transportation infrastructure includes major airports Ronald Reagan Washington National and Washington Dulles International, several lines of the Washington Metro subway system, the Virginia Railway Express suburban commuter rail system, transit bus services, bicycle lanes and trails, and an extensive network of Interstate highways and expressways.
Notable features of the region include the Pentagon and the Central Intelligence Agency, and the many companies which serve them and the federal government. The area's attractions include various monuments and Colonial and Civil War-era sites such as Mount Vernon and Arlington National Cemetery. It is the most affluent region in the nation.
The most common definition of Northern Virginia includes those counties and independent cities on the Virginia side of the Washington-Baltimore-Northern Virginia Combined Statistical Area in 2010 this included the counties of Arlington, Clarke, Culpeper, Fairfax, Fauquier, Frederick, King George, Loudoun, Prince William County, Spotsylvania, Stafford, and Warren, and the independent cities of Alexandria, Falls Church, Fairfax, Fredericksburg, Manassas and Manassas Park.
Most narrowly defined, Northern Virginia consists of the counties of Arlington and Fairfax; as well as the independent cities of Alexandria, Falls Church, Fairfax.
Businesses, governments and non-profit agencies may define the area considered "Northern Virginia" differently for various purposes Beyond the areas closest to Washington, D.C., many communities also have close economic ties, as well as important functional ones regarding transportation issues such as roads, railroads, and airports.