The Barcroft–South Fairlington Line, designated as Route 22A, Route 22C, or Route 22F, is a daily bus route operated by the Washington Metropolitan Area Transit Authority between Ballston–MU station of the Orange and Silver lines of the Washington Metro or Skyline City (22F) and Pentagon station of the Yellow and Blue lines of the Washington Metro. The 22 Line trips are roughly 20 minutes during peak hours, 30 minutes during off peak, and 60 minutes on weekends. This line provides service to Ballston or Skyline City and the Pentagon Transit Center from the neighborhoods of Arlington County, Fairfax County and Alexandria.

Ballston–MU station is a side platformed Washington Metro station in Arlington County, Virginia. The station opened on December 1, 1979, and is operated by the Washington Metropolitan Area Transit Authority (WMATA). The station is part of the Orange and Silver Lines and serves the transit-oriented community of Ballston, Ballston Quarter, and Marymount University (MU).