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When the canal opened in 1825, seven locks dotted the 14 kilometres that separate the Montréal harbour from Lake Saint-Louis: three near the harbour, one at Saint-Gabriel, two at Côte-Saint-Paul and one at Lachine. When the canal was enlarged the first time (1843-1848), the number of locks was reduced from seven to five.
The Lachine Lock Visitor Service Centre stands at the entrance to the canal. Inside an exhibit presents the history of the canal, and outside an interpretive trail explains its vestiges.