A Hog's Back is a ridge of limestone that looks like the ridged back of a hog. The Hog's Back in Ottawa was, originally, a set of waterfalls which marked the end of a seven-mile stretch of shallow water along the Rideau River. The river at this point was 170 feet wide and an elevation difference to the Ottawa River of over 100 feet. From teh Hog's Back travelling through rapids and shallows until it went over the 30 foot Rideau Falls into the Ottawa River.
Upstream from Hogs Back were several sections of rapids including Three Rock Rapids. During the War of 1812, the need was seen to build an inland route to get goods and troops to Kingston, then the capital of Canada, should the Americans cut off access via Lake Ontario and the St. Lawrence River.
Colonel By, after whom By Town (later Ottawa) was named, was given the enormous task of building a canal between By Town on the Ottawa River, and Kingston on Lake Ontario.
During 1828 and 1829, work began on the building of the dam at Hog's Back Falls.
In 1832, the Rideau Canal opened. It is the oldest canal in continuous use in North America. It never saw use for its intended purpose of defence, but it served as a major transportation route until 1875, when the railway made its usefulness for transport obsolete. Still, it has endured and is used for recreational travel.
Sadly, Colonel By, in disgrace, due to scandals over cost over-runs in the building of the canal, died at age 52, his feat unrecognised until long after his death.