at the
Prince William–
Fairfax County border SR 123 begins at an intersection with US 1 (Richmond Highway) between the
Woodbridge station serving
Amtrak and the
Fredericksburg Line of
Virginia Railway Express station and US 1's bridge over the Occoquan River in Woodbridge. The state highway heads north as Gordon Boulevard, a four- to six-lane
divided highway. SR 123 meets I-95 at a
partial cloverleaf interchange that contains a reversible ramp to and from the Interstate's
HOV lanes in the direction of Washington. There is no access from southbound I-95 to southbound SR 123; that movement is provided indirectly via I-95's interchange with US 1 across the river in Fairfax County. The Route 123 and I-95 Commuter Lot, a
park and ride facility, is located within the southeast quadrant of this interchange. Past the interchange, the route heads east of the Occoquan Commuter Lot park and ride. The state highway passes through the eastern edge of the town of
Occoquan and crosses the Occoquan River on a six-lane bridge. SR 123 continues into Fairfax County as Ox Road, which passes through the western part of
Lorton. The state highway passes by the former
Lorton Reformatory and reduces to four lanes north of SR 611 (Furnace Road). SR 123 passes northwest along the edge of the suburban communities of
Laurel Hill,
Crosspointe, and
South Run. The state highway serves the park surrounding
Burke Lake, then veers north through a partial cloverleaf interchange with SR 286 (Fairfax County Parkway) to the west of
Burke Centre. SR 123 crosses over
Norfolk Southern Railway's
Washington District rail line, which also carries the
Manassas Line of Virginia Railway Express, at
Springfield. north of downtown
Fairfax North of its intersection with
SR 620 (Braddock Road), SR 123 passes along the west side of the campus of George Mason University, which includes the
EagleBank Arena. The university's athletic complex, including
George Mason Stadium, lies to the west of the state highway south of its intersection with University Drive, which heads east onto the campus as
SR 383. North of University Drive, SR 123 enters the city of Fairfax and its name changes to Chain Bridge Road. The highway becomes undivided north of Judicial Drive; the state highway passes the
Barbour House, the
Historic Fairfax County Courthouse, and the Fairfax County offices and judicial center. North of
SR 236 (Main Street), SR 123 reduces to two lanes and passes through an
S-curve, then heads through a residential area before expanding to a four-lane divided highway at its intersection with US 29 and US 50 (Fairfax Boulevard). SR 123 leaves the city of Fairfax at its partial cloverleaf interchange with I-66; the interchange includes a flyover ramp from westbound I-66 to southbound SR 123. The state highway curves northeast through
Oakton, then enters the town of Vienna and becomes four-lane undivided Maple Avenue just south of its intersection with
SR 243 (Nutley Street). SR 123 intersects the
Washington and Old Dominion Trail adjacent to the Vienna Town Green. The state highway becomes a divided highway named Chain Bridge Road again on leaving the town limits and entering Tysons, at the southwest edge of which SR 123 has a partial cloverleaf interchange with SR 7 (Leesburg Pike). SR 123 expands to six lanes and begins to parallel
Washington Metro's
Silver Line and intersects SR 684 (International Drive) before passing between a pair of shopping malls:
Tysons Galleria to the north and
Tysons Corner Center to the south. At the eastern edge of Tysons, SR 123 passes under Westpark Drive has a
cloverleaf interchange with I-495 (Capital Beltway). The state highway, now named Dolley Madison Boulevard, follows the Silver Line northeast through office parks to a partial cloverleaf interchange with SR 267 (Dulles Toll Road), which leads west to the Dulles Access Road (unsigned SR 90004) and
Washington Dulles International Airport and east to I-66. There is no access from northbound SR 123 to westbound SR 267; that movement requires using I-495. North of the interchange, in the hamlet of
Lewinsville, the state highway reduces to four lanes and intersects SR 694 (Lewinsville Road), which provides access to the National Counterterrorism Center. SR 123 passes through McLean, the center of which is accessed via
SR 309 (Old Dominion Drive). East of the center of McLean, SR 123 passes by the preserved
Salona estate and close to
Hickory Hill—a historic house on Chain Bridge Road that was home to
Robert F. Kennedy—in Langley, where the state highway meets the eastern end of
SR 193 (Old Georgetown Pike). That state highway provides access to the
Claude Moore Colonial Farm on the campus of the
George Bush Center for Intelligence, the headquarters of the Central Intelligence Agency. The agency's southern main entrance is on SR 123. East of its partial cloverleaf interchange with the George Washington Memorial Parkway, the state highway's name becomes Chain Bridge Road and reduces to two lanes as it descends into the valley of the Potomac River. SR 123 passes by the
Marden House before entering the northwestern corner of Arlington County and meeting the northern end of SR 120 (Glebe Road). There, SR 123 turns north and crosses the Potomac River into Washington on the three-lane Chain Bridge, which leads to the
Clara Barton Parkway into Maryland and Canal Road, which follows the river east to
Georgetown. ==History==