The Trent–Severn Waterway is a 386-kilometre-long (240 mi) canal route connecting Lake Ontario at Trenton to Georgian Bay, Lake Huron, at Port Severn. Its major natural waterways include the Trent River, Otonabee River, Kawartha Lakes, Lake Simcoe, Lake Couchiching and Severn River. Its scenic, meandering route has been called "one of the finest interconnected systems of navigation in the world".
The canal was surveyed as a military route, but the first lock was built in 1833 as a commercial venture. This connected a number of lakes and rivers near the centre of the waterway, opening a large area to navigation by steamship. The government had begun construction of three additional locks when the Upper Canada Rebellion of 1837 broke out. This led the government to re-examine the project, concluding that the route would have too many locks to allow rapid movement for military purposes. They decided that the locks under construction would be completed, but the rest could be turned into timber slides. This left the completed inland section with no outlet, which business interests addressed by connecting to the route with a number of new toll roads, plank roads, and later, railways.