Southwold is a township in Elgin County, in Ontario, Canada, located on the north shore of Lake Erie. It is a rich agricultural zone producing predominantly corn and soybeans. It is part of the London census metropolitan area.

Elgin County is a county of the Canadian province of Ontario with a 2016 population of 50,069. Its population centres are St. Thomas, Aylmer, Port Stanley, Belmont, Dutton and West Lorne. The county seat is St. Thomas, which is separated from the county but within its geographic boundary.