Saint-Léon-le-Grand is a parish municipality in the Maskinongé Regional County Municipality in the Mauricie region of the province of Quebec, Canada.DemographicsPopulation trend: Population in 2011: 992 (2006 to 2011 population change: 2.8%) Population in 2006: 965 Population in 2001: 966 Population in 1996: 955 Population in 1991: 925 Private dwellings occupied by usual residents: 388 (total dwellings: 401)Mother tongue: English as first language: 0% French as first language: 100% English and French as first language: 0% Other as first language: 0%