VALLEYFIELD, town and port of entry, Beauharnois county, Quebec, Canada, 25 m. S.W. of Montreal, at the foot of Lake St Francis-an expansion of the river St Lawrence—and at the head of the Beauharnois canal. Pop. (1891) 5515; (1901) 11,055. It is a station on the Canada Atlantic and New York Central railways, and a port of call for all steamers plying between Montreal and Lake Ontario ports. It is the see of a Roman Catholic bishop, and contains a college and a convent. It has extensive cotton, flour, canning and paper mills.