Tecumseh is a town in Essex County in Southwestern Ontario, Canada. It is on Lake St. Clair east of Windsor and had a population of roughly …Tecumseh is a town in Essex County in Southwestern Ontario, Canada. It is on Lake St. Clair east of Windsor and had a population of roughly 23,300 as of the 2021 census according to Statistics Canada. It is part of the Windsor census metropolitan area, and is a part of the Windsor-Essex County region along with Amherstburg, Kingsville, Lakeshore, LaSalle and Leamington. Tecumseh was originally a Franco-Ontarian settlement.