Granite stones weighing more than 1,000 pounds and averaging 4-6 feet long lie scattered along the east bank of the Dismal Swamp Canal and under its water, each with a unique hand-chiseled numeral and made from granite not found in Virginia. The stones were likely created when the United States Government, recognizing by 1816 the canal’s strategic and financial importance, supported improvements that turned the muddy hand-dug ditch into a "liquid road" between North Carolina and Virginia, including replacing the original timber locks with stone lift locks. Granite was brought from Newark, New Jersey, and cut on site, and Virginia Canals and Navigations Society scholars believe this work occurred between 1819-1820. The stones were most likely intended as mile markers for the canal and adjacent towpath or road, where tolls were calculated by the mile for vessels tracked through by manpower or horse and for travelers using the towpath, and the discovered stones have been found near where mile marks would fall along the canal’s 23-mile length measured south from Deep Creek Lock. They may also have served as beacons marking trouble spots, timber fall, and other problems. By 1896, after traffic shifted to the larger Albemarle and Chesapeake Canal and tolls declined, the canal had fallen into general decay and was sold to a private company, whose steam shovels widened it to twice its former width, destroyed the toll road and towpath, and ended mile-based tolls in favor of charges by the load; the disordered positions of the stones suggest they were tossed aside rather than reset and maintained.