Southwestern Ontario  Southwestern Ontario is a secondary region of Southern Ontario in the Canadian province of Ontario. It occupies most of the Ontario Peninsula bounded by Lake Huron, including Georgian Bay, to the north and northwest; the St. Clair River, Lake St. Clair, and Detroit River, to the west; and Lake Erie to the south. To the east, on land, Southwestern Ontario is bounded by Central Ontario and the Golden Horseshoe. The region had a population of 2,583,544 in 2016. It is sometimes further divided into "Midwestern Ontario" covering the eastern half of the area and the heart of Southwestern Ontario encompassing the western half of the region. Municipalities along the eastern side of Southwestern Ontario near the Grand River, which include Wellington County (containing Guelph), the Region of Waterloo (containing Kitchener, Waterloo and Cambridge) and Brant County (containing Brantford) are also classified by the Government of Ontario as part the Greater Golden Horseshoe region that surrounds western Lake Ontario. Some non-profit organizations, government bodies and news organizations also classify a larger swath of the eastern side of Southwestern Ontario, that is the area from Huron County, Bruce County and Grey County in the north, southward through Dufferin County, Wellington County, the Waterloo Region, Perth County and Oxford County, and sometimes south to Brant County and Norfolk County on Lake Erie as being "Midwestern Ontario." This thereby places only the counties southwest of this in their definition of Southwestern Ontario, although in some cases Perth County is also grouped in Southwestern Ontario. Southwestern Ontario was first settled by Europeans in the early 18th century, when it was part of the Royal Province of New France. One of the oldest continuous settlements in the region is Windsor, which originated as a southerly extension of the settlement of Fort Detroit in 1701. With the transfer of New France to British control in 1763, the region was part of the British Province of Quebec, 1774 to 1791; the Province of Upper Canada, 1791 to 1841; and the Canada West division of the Province of United Canada, 1841 to Confederation in 1867, when United Canada was formally partitioned into the provinces of Ontario and Quebec. During the 19th century and early 20th century, the largest city in Southwestern Ontario was Windsor; however, as both cities grew, Windsor was outpaced by the faster growth of London, and passed the mantle of regional anchor to that city in the 1960s.