Canal this trend. Yet in other countries canals grew in size as construction techniques improved. During the 19th century in the US, the length of canals grew from to over 4,000, with a complex network making the Great Lakes navigable, in conjunction with Canada, although some canals were later drained and used as railroad rights-of-way. In the United States, navigable canals reached into isolated areas and brought them in touch with the world beyond. By 1825 the Erie Canal, long with 36 locks, opened up a connection from the populated Northeast to the Great Lakes. Settlers flooded into regions serviced by
Rideau Canal canal to Kingston and out into Lake Ontario. The objective was to bypass the stretch of the St. Lawrence bordering New York; a route which would have left British supply ships vulnerable to an attack or a blockade of the St. Lawrence. The canal also served a commercial purpose. The Rideau Canal was easier to navigate than the St. Lawrence River because of the series of rapids between Montreal and Kingston. As a result, the Rideau Canal became a busy commercial artery from Montreal to the Great Lakes. However, by 1849, the rapids of the St. Lawrence had been tamed