State Route 28 (SR 28) in the U.S. state of Virginia is a primary state highway that traverses the counties of Loudoun, Fairfax, Prince William, and Fauquier in the U.S. state of Virginia. The route serves as a major artery in the Northern Virginia region, with it being an important two-lane highway in rural Fauquier and Prince William Counties, the main thoroughfare through Manassas and Manassas Park, and a high-capacity freeway through Fairfax and Loudoun Counties.