Wordorigins.org

The province of Alberta is named for Princess Louise Caroline Alberta (1848-1939), daughter of Queen Victoria and Prince Albert. The province was named in 1882 by her husband, John Campbell, the Marquess of Lorne, who was governor-general of Canada from 1878-1883. At the time it was district of the Northwest Territories, becoming a province in 1905.

(Sources: Dictionary of Canadian Place Names; Illustrated Dictionary of Place Names)