Parry Sound District, Ontario in the context of "District Municipality of Muskoka"

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. 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.

The Georgian Bay (French: Baie Georgienne) is a large bay of Lake Huron, in the Laurentia bioregion. It is located entirely within the borders of Ontario, Canada. The main body of the bay lies east of the Bruce Peninsula and Manitoulin Island. To its northwest is the North Channel.

The Georgian Bay is surrounded by (listed clockwise) the districts of Manitoulin, Sudbury, Parry Sound and Muskoka, as well as the more populous counties of Simcoe, Grey and Bruce. The Main Channel separates the Bruce Peninsula from Manitoulin Island and connects the Georgian Bay to the rest of Lake Huron. The North Channel, located between Manitoulin Island and the Sudbury District, west of Killarney, was once a popular route for steamships and is now used by a variety of pleasure craft to travel to and from the Georgian Bay.

Northeastern Ontario is a secondary region of Northern Ontario in the Canadian province of Ontario, which lies north of Lake Huron and east of Lake Superior. Greater Sudbury is its largest settlement.

Northeastern Ontario consists of the districts of Algoma, Sudbury, Cochrane, Timiskaming, Nipissing and Manitoulin. For some purposes, Parry Sound District and Muskoka District Municipality are treated as part of Northeastern Ontario although they are geographically in Central Ontario. These two divisions are coloured in green on the map.