McNair is a census-designated place located in the Oak Hill section of Fairfax County, Virginia, United States. It is directly to the east of Washington Dulles International Airport. The population as of the 2020 census was 21,598. Much of the population resides in the McNair Farms planned community. The community has a school called McNair Elementary.
McNair is also home to the Dulles Corner Business Park, home to the headquarters of Airbus Group, Inc. and Northrop Grumman Technical Services.
McNair was first listed as a census designated place in the 2010 U.S. census.
As of the 2020 census, McNair had a population of 21,598. The median age was 32.2 years. 23.2% of residents were under the age of 18 and 4.4% of residents were 65 years of age or older. For every 100 females there were 104.1 males, and for every 100 females age 18 and over there were 103.6 males age 18 and over.
100.0% of residents lived in urban areas, while 0.0% lived in rural areas.
There were 8,972 households in McNair, of which 33.7% had children under the age of 18 living in them. Of all households, 44.0% were married-couple households, 24.7% were households with a male householder and no spouse or partner present, and 25.0% were households with a female householder and no spouse or partner present. About 30.6% of all households were made up of individuals and 3.5% had someone living alone who was 65 years of age or older.
There were 9,673 housing units, of which 7.2% were vacant. The homeowner vacancy rate was 1.9% and the rental vacancy rate was 6.8%.
The population as of the 2010 census was 17,513.
The CDP is in northwestern Fairfax County, bordered to the northeast by the town of Herndon, to the east by Reston, to the south by Floris, and to the northwest by Loudoun County. The Dulles Toll Road (Virginia State Route 267) forms the northern edge of the CDP, and Virginia State Route 28 (Sully Road) forms part of the western border. Via the Dulles Toll Road and Interstate 66 it is east to downtown Washington, D.C.
According to the U.S. Census Bureau, the McNair CDP has a total area of , of which , or 0.85%, is water.