 The district municipality occupies the western half of the county and its administrative seat is in the village of Sherbrooke.In the 2016 Census of Population conducted by Statistics Canada, the Municipality of the District of St. Mary's recorded a population of 2,233 living in 1,042 of its 1,667 total private dwellings, a change of from its 2011 population of 2,354.With a land area of , it had a population density of in 2016.