The Blackwater River of southeastern Virginia flows from its source near the city of Petersburg, Virginia for about 105 miles (170 km) through the Inner Coastal Plain region of Virginia (part of the Atlantic Coastal Plain). The Blackwater joins the Nottoway River to form the Chowan River, which empties into Albemarle Sound. The Blackwater-Nottoway confluence forms the boundary between Virginia and North Carolina. Overview The Blackwater River is a true blackwater river. Its water is clear, dark, slightly acidic, and tannin stained. Its drainage basin contains many swamps. The river's flood plain is mostly forested and swampy, including bald cypress and tupelo swamp forests. The upper Blackwater River is called Blackwater Swamp. In this region of Virginia, many streams are called "swamps" but still function like streams in being long and linear, with water moving from one end to the other and laid out in a normal stream tributary network. In contrast, some of the region's wetlands are not streams, such as the bog-like pocosins found on the higher land between swamp-stream drainages. The Blackwater River was a transportation route in the 17th and 18th centuries, connecting the Chesapeake Bay settlements with the Albemarle Settlements. It was one of the few rivers of colonial Virginia that did not empty into Chesapeake Bay yet lay close to the colony's oldest settlements on the James River. Settlements in the Blackwater's drainage basin were founded very early in Virginia's history. As a result, the Blackwater River became one of the early migration routes southward from the James River into the region then called Southside Virginia, and beyond into the Albemarle District of Carolina (later North Carolina). Today's usual definition of Southside differs somewhat from that of colonial times. Course The Blackwater River originates in several swamps within, or just south of, the city of Petersburg. It flows southeast through Prince George County, where it is called Blackwater Swamp. It then forms part of the border between Surry County and Sussex County, where its name becomes Blackwater River. It collects tributaries called Warwick Swamp, Otterdam Swamp, Coppahaunk Swamp, and Cypress Swamp. In southern Surry County, the Blackwater River turns south and forms the border between Isle of Wight County and Southampton County. It collects tributaries called Terrapin Swamp, Antioch Swamp, Seacock Swamp, Corrowaugh Swamp, and Kingsale Swamp. The city of Franklin lies on its west bank at the river's head of navigation. While canoes