Merrickville was established in 1794 when the American William Merrick came from Massachusetts to set up grist and lumber mills at the falls, and throughout the 19th century it remained an important industrial centre on the Rideau with grist, shingle, and wool-carding mills whose products were carried between river settlements. It was one of the few villages on the waterway settled before construction of the canal, and some abandoned mill buildings still stand on the small island beside the locks. The locks here are uniquely arranged with a small basin between each lock so they could follow a natural depression in the ground and reduce excavation after the land was cleared of forest. Between 1826 and 1832, an old Indian canoe route along the Rideau and Cataraqui Rivers was transformed by command of the British government into the Rideau Canal, a 202 km (126 miles) waterway made navigable by 47 locks grouped in 22 stations with associated dams and weirs. Designed and superintended by the Royal Engineers under Lieutenant Colonel John By and built by local contractors, the canal was intended to give the British army a safe inland supply route that avoided the exposed St. Lawrence after the War of 1812. Although blockhouses stood along the waterway, the Rideau's role was peaceful, carrying settlers and supplies into the interior until the middle of the 19th century, passing to the colonial government of Canada in 1856 after the danger of war with the United States had waned, remaining important for local commercial traffic until the rise of the automobile and better roads around World War I, and later becoming busier than ever through recreational boating.