 It began construction in the 1980s through the Halle Companies and is still expanding today in the town center with commercial and office space and in the subdivisions with more single-family homes.Kingstowne has its own ZIP code, 22315, a substation of the Alexandria U.S. Post Office.The Kingstowne CDP is in southeastern Fairfax County, bordered to the north and west by Franconia, to the northeast by Rose Hill, to the southeast by Hayfield, to the south by Fort Belvoir, and for a short distance at its southwestern end by Newington.