Severn is a township in south-central Ontario, Canada, located between Lake Couchiching, and the Severn River (both are part of the Trent–Severn Waterway) in Simcoe County. The current township was founded on January 1, 1994, as part of the restructuring of Simcoe County, by amalgamating the village of Coldwater with the townships of Matchedash and Orillia, plus portions of the townships of Medonte and Tay.