Franklin County is located in the Blue Ridge foothills of the Commonwealth of Virginia. As of the 2020 census, the population was 54,477. Its county seat is Rocky Mount. Franklin County is part of the Roanoke Metropolitan Statistical Area and is located in the Roanoke Region of Virginia. The Roanoke River forms its northeast boundary with Bedford County.

The Roanoke River runs 410 miles (660 km) long through southern Virginia and northeastern North Carolina in the United States. A major river of the southeastern United States, it drains a largely rural area of the coastal plain from the eastern edge of the Appalachian Mountains southeast across the Piedmont to Albemarle Sound. An important river throughout the history of the United States, it was the site of early settlement in the Virginia Colony and the Carolina Colony. An 81-mile (130 km) section of its lower course in Virginia between the Leesville Lake and Kerr Lake is known as the Staunton River, pronounced, as is the Shenandoah Valley city of that name. It is impounded along much of its middle course to form a chain of reservoirs.