St. Catharines is a federal electoral district in the Niagara Region of Ontario, Canada, that has been represented in the House of Commons of Canada since 1968. It consists of the part of the City of St. Catharines lying east and north of a line drawn from Lake Ontario: Courtleigh Road, Third Street Louth, the QEW, Highway 406, First Street Louth, St. Paul Street West, St. Paul Crescent, Twelve Mile Creek, Glendale Avenue, Merrit Street and Glendale Avenue.