State Route 645 in Fairfax County, Virginia is a secondary state highway. There are six portions, three of them being major, named Wall Road, Lees Corner Road, Stringfellow Road, Clifton Road, Main Street (in the Town of Clifton) and Burke Lake Road. There are also numerous overlaps (mostly unposted): some include SR 657 / Centreville Road, U.S. Route 50, SR 652 (Burke Rd), SR 612 (Yates Ford Rd/Henderson Rd), and SR 641. A concurrency used to exist at US 29 near Centreville until the 1990s. Route description A map of Fairfax County shows that SR 645 is somewhat circuitous: Wall Road is east–west, Lees Corner Road, Stringfellow Road, and the northern part of Clifton Road are north–south, the rest of Clifton Road is mostly east–west, and Burke Lake Road is northeast-southwest. Wall Road SR 645 starts in Oak Hill at a cul-de-sac between SR 28 (Sully Road) and SR 657 (Centreville Road). It goes one block and terminates at SR 657. Lees Corner Road At this point SR 645 turns south and is concurrent with SR 657, Centreville Road. SR 645 then turns southeast along Lees Corner Road in Herndon. It terminates at U.S. Route 50, Lee Jackson Memorial Highway, in Chantilly. Stringfellow Road At this point SR 645 turns east and is concurrent with US 50. SR 645 then turns south in Fairfax. Once south of U.S. 50, Stringfellow Road serves as the ZIP Code border between Chantilly (20151) and Fairfax (22033). The road passes through the Greenbriar development, where it intersects with SR 4831, Poplar Tree Road. It then passes by Fair Lakes' western end where the Fair Lakes Parkway terminates at SR 645. After this, Stringfellow Road passes east of the Stringfellow Road Park & Ride, a park and ride facility, and has an interchange with Interstate 66. From 5:30 to 9:30 a.m. weekdays, HOV-2 traffic is allowed to enter I-66 eastbound from Stringfellow Rd. Westbound traffic can exit onto Stringfellow Road at all other times, but the exit is restricted to HOV-2+ traffic weekdays from 3:00 to 7:00 p.m. South of the I-66 interchange, Stringfellow Road heads to an intersection with U.S. Route 29 (Lee Highway) at the Fairfax/Centreville/Clifton border. A project was completed to widen Stringfellow Road from SR 7735 (Fair Lakes Boulevard) to US 50 from two lanes to four (Stringfellow Road from Interstate 66 to US 29 was widened to four lanes in