the eastern end of SR 235 (Mount Vernon Highway) just west of Little Hunting Creek. US 1 expands to six lanes as it curves north through Hybla Valley and Groveton. On the southern edge of Huntington, the U.S. Route has a tangent intersection with Kings Highway, which heads north as SR 241. US 1 veers northeast and expands to eight lanes at Huntington Avenue and maintains that width until its major interchange with the Capital Beltway (I-95 and I-495) at Cameron Run on the boundary between Fairfax County and the independent city of Alexandria. The interchange includes several flyovers and provides partial access to the express and local lanes of the beltway in both directions. US 1 continues north as a six-lane divided Patrick Street into Old Town Alexandria, which, at Wilkes Street, splits into a one-way pair, Patrick Street northbound and Henry Street southbound. The highway intersects SR 236 (Duke Street) and SR 7 (King Street) within Old Town. North of Montgomery Street, the directions come together as Henry Street, which crosses the Monroe Avenue Bridge over the RF&P Subdivision rail line and the Washington Metro's Blue and Yellow lines. US 1 again becomes Richmond Highway (changed from Jefferson Davis Highway in 2019) north of the railroad tracks. The four-lane divided highway, which contains the Metroway bus rapid transit course in its median, passes between Potomac (and the Del Ray neighborhood) to the west and a large residential and commercial development built on what was formerly Potomac Yard to the east. Metroway merges with the main streams of US 1 traffic, which expand to three lanes each way as the highway approaches the northern city limit at Four Mile Run. The U.S. Route leaves Alexandria for Arlington County and has an intersection with the southern end of SR 120 (Glebe Road). US 1—again bearing the name Richmond Highway—continues through the urban village of Crystal City, where the highway has a trumpet interchange with SR 233, a connector to Ronald Reagan Washington National Airport. The route becomes a freeway north of 20th Street South and has a diamond interchange with 15th Street south on the eastern edge of Pentagon City. US 1 then joins I-395 on Henry G. Shirley Memorial Highway via a pair of flyover ramps; Richmond Highway continues north as SR 110, which passes by the Pentagon and Arlington National Cemetery on its way to Rosslyn. I-395 and