Southern Ontario is a primary region of the province of Ontario, Canada, the other primary region being Northern Ontario. It is the most densely populated and southernmost region in Canada. The exact northern boundary of Southern Ontario is disputed; however, the core region is situated south of Algonquin Park, the latter being in an area of transition between coniferous forest north of the French and Mattawa Rivers and southern deciduous forest. It covers between 14 and 15% of the province, depending on the inclusion of the Parry Sound and Muskoka districts which also lie in the transitional area between northern and southern forest regions. With more than 12.7 million people, the region is home to approximately one-third of Canada's population of 35.1 million.
