Etymology

The region is often spelled "northern Virginia", although according to the USGS Correspondence Handbook the 'n' in Northern Virginia should be capitalized as it is a place name rather than a direction or general area.

The name "Northern Virginia" does not seem to have been used in the early history of the area. According to Johnston, some early documents and land grants refer to the "Northern Neck of Virginia" (see Northern Neck Proprietary), and they describe an area which began on the east at the western shore of the Chesapeake Bay and includes a territory that extended west, including all the land between the Potomac and Rappahannock rivers, with a western boundary called the Fairfax line. The Fairfax line, surveyed in 1746, ran from the first spring of the Potomac (still marked today by the Fairfax Stone) to the first spring of the Rappahannock, at the head of the Conway River. The Northern Neck was composed of 5,282,000 acres (21,380 km2), and was larger in area than five of the modern U.S. states.

This monument, at the headspring of the Potomac River, marks one of the historic spots of America. Its name is derived from Thomas Lord Fairfax who owned all the land lying between the Potomac and Rappahannock Rivers. The first Fairfax Stone, marked "FX", was set in 1746 by Thomas Lewis, a surveyor employed by Lord Fairfax. This is the base point for the western dividing line between Maryland and West Virginia.

— Fairfax Stone inscription

Early development of the northern portion of Virginia was in the easternmost area of that early land grant, which encompasses the modern counties of Lancaster, Northumberland, Richmond, and Westmoreland. At some point, these eastern counties came to be called separately simply "the Northern Neck", and, for the remaining area west of them, the term was no longer used. (By some definitions, King George County is also included in the Northern Neck, which is now considered a separate region from Northern Virginia.)

One of the most prominent early mentions of "Northern Virginia" (sans the word Neck) as a title was the naming of the Confederate Army of Northern Virginia during the American Civil War (1861–1865).

Defining "Northern Virginia" Washington-Baltimore-Northern Virginia CSA

"Northern Virginia" is more of a functional name than a rigidly defined area. It has no authoritative definition (like the legal boundaries of states, counties, or cities). 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, King George, Loudoun, Prince William, Spotsylvania, Stafford, and Warren, and the independent cities Alexandria, Falls Church, Fairfax, Fredericksburg, Manassas, and Manassas Park.

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.

Under broad and varying criteria, one might also consider Northern Virginia to include the counties of Frederick, Madison, Page, Rappahannock, Shenandoah, and independent city Winchester.