The Blackwater River, the easternmost river in the basin, falls entirely within the coastal plain. Originating in swamps south of Petersburg and meandering southeast for 105 miles where it forms the border between Sussex and Surry counties, the Blackwater meets the Nottoway River just south of Franklin, VA at the North Carolina state line.
Extensive tupelo and cypress swamps flank the river, including a number of 1,000-year-old specimens. Sandy ridges along the eastern banks support globally rare longleaf pine forests.
It is a true "blackwater" river meaning that its water is clear, dark, slightly acidic, and tannin stained.
Culturally, the Blackwater has a rich history. During the American Revolution, it served as Virginia's westernmost boundary for colonization from Jamestown. As early at 1713, the town of South Quay (pronounced "key") hosted a settlement and small shipyard along this river and was touted as the largest interior port in the tidewater region.