Rappahannock River Canal Path and Old Mill Park

The path runs along the Rappahannock near where the river crosses the fall line — Fredericksburg sits at the fall line, where rivers stop being navigable and goods had to portage overland. The Wikipedia article on the James River and Kanawha Canal describes a different system entirely, one that ran west from Richmond toward the mountains, but the principle was the same: Virginia's rivers were commercial highways, and the fall line was the choke point. Towns that solved it prospered.

Fredericksburg was named in 1728 for Frederick, Prince of Wales, positioned at the head of navigation on the Rappahannock as a formal trading center for tobacco export. During the Civil War, it sat halfway between Washington and Richmond — the capitals of the opposing armies — and witnessed the Battle of Fredericksburg in 1862, which caused long-term disruption to its infrastructure and population. More than 10,000 African Americans in the region left slavery for freedom in 1862 alone, getting behind Union lines.

Old Mill Park is managed by the city now. The official website lists it among Fredericksburg's parks and recreation facilities. If you want to walk a waterside trail in Fredericksburg, this is the option.