In the 2021 Census of Population conducted by Statistics Canada, Lac-Saint-Joseph had a population of 304 living in 167 of its 334 total private dwellings, a change of 16.9% from its 2016 population of 260. With a land area of 33.65 km2 (12.99 sq mi), it had a population density of 9.0/km2 (23.4/sq mi) in 2021.[5]