Southern Ontario

Southern Ontario
Primary region
Southern Ontario
██ Core area ██ Extended area
Coordinates: 44°00′N 80°00′W / 44.000°N 80.000°W / 44.000; -80.000
Country	Canada
Province	Ontario
Area
• Total	114,217 km2 (44,099 sq mi)
• Core area	101,264 km2 (39,098 sq mi)
• Extended area	12,953 km2 (5,001 sq mi)
Population  (2021)
• Total	13,481,332
• Density	118.0/km2 (306/sq mi)
• Core area	13,367,749
• Extended area	113,583
Demonym	Southern Ontarian
Time zone	UTC−5 (EST)
• Summer (DST)	UTC−4 (EDT)
Postal code prefixes	K, L, M, N
Area code(s)	226, 249, 289, 343, 365, 416, 437, 519, 548, 613, 647, 705, 905

Southern Ontario is a primary region of the Canadian province of Ontario. It is the most densely populated and southernmost region in Canada, with approximately 13.5 million people, approximately 36% of Canada's population of 37 million.^[1] The region lies south of the province's other primary region, Northern Ontario, although the exact northern boundary of Southern Ontario is disputed. However, its 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. Southern Ontario differs greatly from Northern Ontario, having a much higher population density, a different climate, and a different culture than its northern counterpart. It is broken into smaller subregions, including Central Ontario, Eastern Ontario, the Golden Horseshoe, and Southwestern Ontario.

The core area of Southern Ontario is part of the Quebec City–Windsor Corridor, which extends northeast into southern Quebec. The transitional northern area of this primary region extends north to the Mattawa River and occupies part of the Grenville Geological Province of the Canadian Shield, which also extends northeast into southern Quebec; most of Northern Ontario lies within the Superior Geological Province.