The Wellington District was a historic district in Upper Canada which existed until 1849. It was formed in 1838 from parts of Huron County, Ontario in the Gore District, Simcoe County in the Home District and Huron County from the London District.
It consisted of Waterloo County and its district town was Guelph.
In 1849, Wellington District was replaced by Waterloo County. In 1852, Berlin, later Kitchener, became the county seat.