Franconia is a census-designated place in Fairfax County, Virginia, United States. The population was 18,943 at the 2020 census. Located just southwest of Alexandria, Franconia has existed as a community since the 1870s, when a station by that name opened on the RF&P Railroad; however, like most of the surrounding area, it only began to develop into its present, suburban form in the 1950s.