Map & Direction: Key Bridge Test Prep headquarter is located off the Lee Jackson Memorial Highway (Route 50) between Fairfax City and Chantilly. Close to Fair Oaks Mall and Exhibition Center, Fair Oaks Hospital, and Chantilly Regional Library. Most convenient to get here through major highways: I-66 (exit 57B), Route 286, Rt. 50, Rt. 28 and Rt. 29.