With a population of 3,645,257 in 2011 and an estimated population of 4,196,457 as of July 1, 2015, it is Canada's fourth-most populous province and most populous of Canada's three prairie provinces. Alberta and its neighbour, Saskatchewan, were established as provinces on September 1, 1905.n the 2011 census, Alberta had a population of 3,645,257 living in 1,390,275 of its 1,505,007 total dwellings, a 10.8% change from its 2006 population of 3,290,350. With a land area of 640,081.87 km 2 (247,136.99 sq mi), it had a population density of 5.7/km 2 (14.7/sq mi) in 2011.