Smiths Falls is a town in Eastern Ontario, Canada, 72 kilometres (45 mi) southwest of Ottawa. As of the 2021 census it has a population of 9,254. It is in the Census division for Lanark County, but is separated from the county. The Rideau Canal waterway passes through the town, with four separate locks in three locations and a combined lift of over 15 metres (49.2 ft).