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.
The township comprises the communities of Amigo Beach, Ardtrea, Buckskin, Buena Vista Park, Burnside, Carlyon, Coldwater, Cumberland Beach, Fesserton, Hamlet, Hampshire Mills, Happyland, Hawkins Corner, Hydro Glen, Lovering, Maple Valley, Marchmont, Medonte, Menoke Beach, Mordolphin, Mount Stephen, Port Severn, Port Stanton, Scarlet Park, Severn Falls, Swift Rapids, Uhthoff, the Uhthoff Hunt Camp, Wilson Point and Washago.
Chief John Aisance and his band of Chippewas (also known as Ojibwa) settled along the Severn River in 1830, calling the place Gissinausebing, which means "cold water." They built a grist mill on the site in 1833, which the Native people owned until 1849. In 1835 a post office was established, and the community was called Coldwater.
After building a sawmill in 1830, the residents also called the community Severn Mills. Around 1850, lumber from this area was being sent out on ships; the village was renamed to Port Severn in 1868. In 1875, the Georgian Bay Lumber Co. was formed, soon to become the major lumber producer in the Severn River watershed.
Coldwater was opened to European settlement in 1836, and was incorporated as a village in 1908. Three weekly newspapers have been published in the community: the Coldwater Planet (1896 to 1928), the Coldwater News (1895 to 1956); and the Coldwater Canadian in 1956.
The settlement expanded rapidly over the next 20 years. In 1896, the mill was struck by lightning and burned to the ground. Since the timber supply in the area had been greatly reduced, the mill was not rebuilt and the population of the village began to decline. With the completion of the Trent–Severn Waterway in this area in 1915, economic activity shifted from lumber to tourism.