Political movement in Canada in the 1830s and '40s.
Reformers in Upper Canada (later Ontario) led by William L. Mackenzie opposed the government in the rebellion of 1837. Reformers in Lower Canada (later Quebec) joined Louis Papineau and his Patriote Party. Reform Party candidates were elected premier (1842–43, 1848–54) in the province of Canada (union of Upper and Lower Canada). In the 1850s the party split between a moderate group, which allied with John Macdonald 's Progressive Conservative Party , and a radical faction, the {{link=Clear Grits">Clear Grits , from which the Liberal Party emerged.