In Centreville and Eastern Loudoun County, SR 620 is a major commuter route, as it empties onto SR 28 (Sully Rd.), which in turn has a nearby interchange with Interstate 66. SR 620 also has major junctions with SR 123, Fairfax County Parkway, and Interstate 495 (Capital Beltway). It has a very large number of residential neighborhoods lining the road, so most of the remainder is also a major commuter artery. The length and positioning of the highway attract motorists that are traveling from one part of Fairfax County to another.