138 (Union Mill Road), then expands to a four-lane divided highway for its four-ramp partial cloverleaf interchange with I-85 before leaving the town of South Hill. US 1 continues northeast as a three-lane road that alternates between two lanes northbound, two lanes southbound, and a center turn lane. The route expands to a four-lane divided highway after entering Brunswick County, where the highway's name becomes Boydton Plank Road, and before crossing the Meherrin River. US 1 reduces to a three-lane road and passes through Meredithville. At Cochran, the highway intersects SR 46 (Christanna Highway) just south of the Christanna Campus of Southside Virginia Community College. US 1 expands to a four-lane divided highway; the southbound lanes pass under a narrow former railroad bridge. The highway has a diamond interchange with I-85, then passes through the southern edge of the town of Alberta, where the U.S. Route meets the eastern end of SR 136 (Church Street). East of Alberta, US 1 becomes three lanes and passes through the adjacent communities of Warfield and Sturgeonville and to the east of Rawlings before expanding to a four-lane divided highway immediately before crossing the Nottoway River into Dinwiddie County. US 1 reduces to three lanes a short distance north of the river and passes through the town of McKenney, where the highway intersects SR 40 (Doyle Boulevard). The highway passes through DeWitt, then expands to a four-lane divided highway and crosses a former railroad line. US 1 crosses Stony Creek and drops to three lanes as it enters the county seat of Dinwiddie and passes Dinwiddie County Court House. Northeast of Dinwiddie, US 1 passes under I-85 with no access and meets the eastern end of Airport Street, which comprises the westernmost segment of US 460 Bus. that connects US 1 with I-85 and US 460 and, to the west of the Interstate, Dinwiddie County Airport. US 1 and US 460 Bus. pass Pamplin Historical Park, which preserves the Petersburg Breakthrough Battlefield, then cross over Norfolk Southern Railway's Norfolk District rail line. The routes expand to a four-lane divided highway at its intersection with SR 142 (Simpson Road), then they meet I-85 and US 460 at a six-ramp partial cloverleaf interchange. US 1 and US 460 Bus. reduce to two lanes plus center turn lane and pass along the western and northern sides of Central State Hospital; on their curve east, the routes meet