List of regions of Canada in the context of "Atlantic Canada"

The Maritimes, also called the Maritime provinces, is a region of Eastern Canada consisting of three provinces: New Brunswick, Nova Scotia, and Prince Edward Island. The Maritimes had a population of 1,899,324 in 2021, which makes up 5.1% of Canada's population. Together with Canada's easternmost province, Newfoundland and Labrador, the Maritime provinces make up the region of Atlantic Canada.

Located along the Atlantic coast, various aquatic sub-basins are located in the Maritimes, such as the Gulf of Maine and Gulf of St. Lawrence. The region is located northeast of New England in the United States, south and southeast of Quebec's Gaspé Peninsula, and southwest of the island of Newfoundland. The notion of a Maritime Union has been proposed at various times in Canada's history; the first discussions in 1864 at the Charlottetown Conference contributed to Canadian Confederation. This movement formed the larger Dominion of Canada. The Mi'kmaq, Wolastoqiyik and Passamaquoddy people are indigenous to the Maritimes, while Acadian and British settlements date to the 17th century. The Maritimes are within the Atlantic time zone, putting them one hour ahead of Quebec and the New England region of the United States.

Central Canada (French: Canada Central, sometimes the Central Provinces) is a Canadian region consisting of Ontario and Quebec, the largest and most populous provinces of the country. Geographically, they are not at the centre of Canada but instead overlap with Eastern Canada toward the east. Because of their large populations, Ontario and Quebec have traditionally held a significant amount of political power in Canada, leading to some amount of resentment from other regions of the country. Before Confederation, the term "Canada" specifically referred to Central Canada. Today, the term "Central Canada" is less often used than the names of the individual provinces.

Western Canada, also referred to as the Western provinces, Canadian West, or Western provinces of Canada, and commonly known within Canada as the West, is a Canadian region that includes the four western provinces just north of the Canada–United States border namely (from west to east) British Columbia, Alberta, Saskatchewan and Manitoba. The people of the region are often referred to as "Western Canadians" or "Westerners", and though diverse from province to province are largely seen as being collectively distinct from other Canadians along cultural, linguistic, socioeconomic, geographic and political lines. They account for approximately 32% of Canada's total population.

The region is further subdivided geographically and culturally between British Columbia, which is mostly on the western side of the Canadian Rockies and often referred to as the "west coast", and the "Prairie Provinces" (commonly known as "the Prairies"), which include those provinces on the eastern side of the Rockies yet west of Ontario - Alberta, Saskatchewan and Manitoba. Alberta and British Columbia are also sometimes subcategorized together, either as the "Rockie Provinces" or "mountain provinces" owing to both hosting large swathes of the mountain range, or due to shared socioeconomic factors such as their highly urbanized populations (three of Canada's five largest cities are Calgary, Edmonton, and Vancouver) and significant interprovincial mobility between the two. Alberta and Saskatchewan, having once been united as a single territory, are also sometimes subcategorized together due to shared political and economic histories, as well as similar historic migratory patterns from Eastern Europe.

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.