From this overall map (which is contracted in the "dry" States across the Rocky Mountains), choose one of three enlargements.
The first highlights the modern waterway network, more than 12 000 miles (19 300 km) of high-capacity waterways maintained and operated by the US Army Corps of Engineers.
The second is a larger-scale view of the heritage canals built in the 19th century across the North Eastern States from Illinois and Indiana through to New Hampshire and North Carolina.
Finally, a zoom from the second map encompasses an area at the borderline between these two networks, geographically, historically and in operational terms. This is the complex and heterogenous network of canals and canalised rivers which extends from New York City to Lake Erie, including the Erie Canal (replaced by the New York State Barge Canal in the early 20th century), the Canadian heritage canals which have remained in operation for nearly 200 years, and most of the man-built sections of the St Lawrence Seaway…

Information about the network:
http://www.usace.army.mil/missions/water.html

Information about the America's Great Loop:
http://www.greatloop.com