Hybla Valley is a census-designated place (CDP) in Fairfax County, Virginia, United States, south of Alexandria. The population was 15,801 at the 2010 census, down from 16,721 in 2000 due to a reduction in area, resulting from some of the eastward neighborhoods including much of Hollin Hills being moved to the Fort Hunt CDP. The population increased to 16,319 in the 2020 census.
The Mason family's Hollin Hall plantation, just south of Alexandria, had become the property of several owners, including Edward Curtis Gibbs and the Wilson family. Thomson Dairy had been founded on the land in the late 19th century, and lasted until Merle Thorpe purchased it in the early 20th century. The various dairy farms, such as Sherwood Farm, Hybla Valley Farm, and Popkins Farm were converted into suburban neighborhoods, while plans for the construction of the George Washington Air Junction and the Hybla Valley Airport began. The civilian airport was proposed to be th