• The Rappahannock River, and its major tributary, the Rapidan River begin on the east slope of the Blue Ridge. From there, they flow eastward across the Piedmont.
• The Rappahannock and the Rapidan join at the tri-county border of Spottsylvania, Culpeper, and Stafford Counties. At Fredericksburg, it crosses the Fall Line.
• Once in the Coastal Plain, it widens considerably before it reaches the Chesapeake Bay.
• The York River forms at the confluence of its northeastern tributary, the Mattaponi River and its southwestern tributary, the Pamunkey River. This occurs at West Point, in the central Coastal Plain.
Confluence of the Mattaponi River (northeastern tributary) and the Pamunkey River (southwestern tributary) to form the York River at West Point, Virginia at the tri-county border of King and Queen, King William, and New Kent Counties. (Map data by Google)
• The Mattaponi River's headwaters are in the Piedmont. There, 4 main tributaries (named the Mat, the Ta, the Po, and the Ni Rivers) join together to form the Mattaponi near the Fall Line.
• The Pamunkey River is formed by the confluence of two tributary rivers that drain the Piedmont: the North Anna River and the South Anna River that converge in near the Fall Line.
• The North Anna River is notable for Lake Anna, a reservoir on the border of Spottsylvania and Louisa Counties. The North Anna Power Station uses the waters of the reservoir to cool its nuclear reactors. (Virginia's other nuclear electric power plant is at Surry, along the James River.)
Google terrain view of Lake Anna on the border of Louisa and Spottsylvania Counties. (Image by Google)