There are two kinds of regions in Canada: those formed at the national level and sometimes used for the Canadian Senate, and those used within the provinces and territories.

National regions
Although these regions have no official status or defined boundaries the Provinces and territories are sometimes informally grouped into the following regions (generally from west to east):

Other regions are:
French Canada
English Canada
Arctic Canada (mostly Inuit -neither English nor French)
Quebec City–Windsor Corridor

Seats in the Senate are equally divided among four regions: Maritimes, Quebec, Ontario, and the West, with special status for Newfoundland and Labrador, and Northern Canada ("the North").

Provincial regions
The provinces and territories are all sub-divided into regions for a variety of official and unofficial purposes. In some provinces, the regions are used for political purposes. In others, they are just geographic areas.

Alberta

Primary and secondary regions
Northern Alberta boreal forest
Peace River Country
Alberta's Rockies
Palliser's Triangle (Alberta portion)
Southern Alberta
Cypress Hills
Calgary Region
Edmonton Capital Region
Central Alberta
Calgary–Edmonton Corridor

British Columbia

Primary, secondary, and local regions
British Columbia Interior
Atlin District
Stikine Country
Peace River Country
Nechako
Bulkley
Cariboo
Interlakes
Fraser Canyon
Chilcotin
Omineca-Prince George
Robson Valley
Kootenays
West Kootenay
Slocan
Arrow Lakes
East Kootenay
Elk Valley
Columbia Valley
Columbia Country
Big Bend Country
Columbia Valley
Okanagan
Boundary
Similkameen
Thompson
Nicola
Bonaparte
Wells Gray-Clearwater
Shuswap
Lillooet-Fraser Canyon
Bridge River Country
South Coast
Lower Mainland
Greater Vancouver
Fraser Valley
Sea-to-Sky Corridor
Pemberton Valley (also part of Lillooet Country)
Gates Valley (also part of Lillooet Country)
Sunshine Coast
Vancouver Island
Greater Victoria
Saanich Peninsula
Western Communities
South-central Island
Cowichan Valley
Chemainus Valley
East-central Island
Nanaimo-Parksville
Comox Valley
North Island
Quatsino Sound
Cape Scott
Queen Charlotte Strait
Johnstone Strait
West Coast of Vancouver Island
Kyuquot Sound
Nootka Sound
Clayoquot Sound
Barkley Sound
Alberni Valley
Juan de Fuca region
Gulf Islands
Southern Gulf Islands
Northern Gulf Islands
Central Coast
Queen Charlotte Strait
Bella Coola Valley
North Coast
Haida Gwaii (formerly Queen Charlotte Islands)
Skeena
Nass
Stewart Country

Manitoba

Primary and secondary regions
Northern Manitoba
Central Manitoba
Interlake
Parkland
Pallisers Triangle (Manitoba portion)
Central Plains
Eastman
Westman
Winnipeg Capital Region
Pembina Valley

New Brunswick

Local regions
Acadian Peninsula
North Shore
Gulf Shore
Fundy Shore
Fundy Isles
Kennebecasis River Valley
Republic of Madawaska
Miramichi Valley
St. John Valley
Tantramar
Greater Shediac
Greater Moncton
Greater Saint John
Greater Fredericton

Newfoundland and Labrador

Primary, secondary, and local regions
Labrador
Labrador West
Labrador Coast
Nunatsiavut
Newfoundland
Avalon Peninsula
Burin Peninsula
Bonavista Peninsula
South Coast
West Coast
Bay of Islands
South Shore Bay of Islands
North Shore Bay of Islands
Corner Brook
Bay St. George
Bay St. George South
Bonne Bay
Gros Morne
Port au Port Peninsula
Great Northern Peninsula
White Bay
Northeast Coast
Fogo Island
Jack City Island

Northwest Territories

Administrative regions of the Government of the Northwest Territories
Inuvik Region
Sahtu Region
Dehcho Region
North Slave Region
South Slave Region

Nova Scotia

Primary and local regions
Cape Breton Island
Industrial Cape Breton
Cape Breton Highlands

Nova Scotia Mainland
Annapolis Valley
Strait of Canso Area
Central Nova Scotia
Eastern Shore
Greater Halifax
Musquodoboit Valley
North Shore
South Shore
Tantramar

Nunavut

Administrative regions
Kitikmeot Region
Kivalliq Region
Qikiqtaaluk Region

Ontario

Primary, secondary, and local regions
Northern Ontario
Northwestern Ontario
Northeastern Ontario
Nickel Belt
Southern Ontario
Central Ontario
Kawartha Lakes
Muskoka
Bay of Quinte
Eastern Ontario
National Capital Region
Ottawa Valley
Thousand Islands
Southwestern Ontario
Georgian Triangle
Bruce Peninsula
Thirty Thousand Islands
Golden Horseshoe
Greater Toronto Area
Niagara Peninsula

Prince Edward Island

Local regions
North Shore
South Shore
Summerside Area
Charlottetown Area

Quebec

Primary and secondary regions
Northern Quebec
Arctic mountains (Quebec portion)
Northern Arctic Shield (Quebec portion) 
Southern Arctic Shield (Quebec portion)
Quebec Taiga Shield 
Hudson Bay Lowlands (Quebec portion)
Quebec Boreal Shield
Southeastern Boreal Shield (Quebec portion)
Southern Quebec
St. Lawrence Lowlands, North Shore (Quebec portion)
St. Lawrence Lowlands, South Shore
Hochelaga Islands
Anticosti Island
Appalachian Mountains (Quebec portion)

Local and administrative regions
Bas-Saint-Laurent
Saguenay–Lac-Saint-Jean
Capitale-Nationale
Mauricie
Estrie
Montreal
Outaouais
Abitibi-Témiscamingue
Côte-Nord (North Shore)
Nord-du-Québec (Northern Quebec)
Gaspésie–Îles-de-la-Madeleine
Chaudière-Appalaches
Laval
Lanaudière
Laurentides
Montérégie
Centre-du-Québec

Saskatchewan

Primary and local regions
Northern Saskatchewan
Palliser's Triangle (Saskatchewan portion)
Carlton Trail Region
East Central Saskatchewan
Regina area
Saskatoon area
Cypress Hills

Yukon

Local regions
Klondike
Southern Lakes

Notes

Regions