High Quality Content by WIKIPEDIA articles! State Route 620 is a secondary state highway in the U.S. state of Virginia, and traverses both Fairfax County and Loudoun County. The entire length of SR 620 is also known as Braddock Road (except for a small section in Centreville called Spindle Court). SR 620 also has a short concurrency with SR 659 / Union Mill Road in Centreville.