Canada occupies 9.98 million square kilometres, making it the second-largest country by total area after Russia. The nation extends 5,514 kilometres from Cape Spear in Newfoundland to the Yukon-Alaska border, and 4,634 kilometres from Middle Island in Lake Erie to Cape Columbia on Ellesmere Island. Canada borders three oceans: the Atlantic to the east, the Pacific to the west, and the Arctic to the north. The country shares an 8,891-kilometre land border with the United States, the world's longest undefended border, including a 2,475-kilometre boundary with Alaska.
The Canadian Shield dominates the country's geography, covering approximately 8 million square kilometres or nearly half the land surface. This Precambrian igneous rock formation, some portions dating to 4.28 billion years ago, curves around Hudson Bay in a horseshoe pattern extending from the Arctic islands through the Northwest Territories, northern Saskatchewan and Manitoba, Ontario, Quebec, and into Labrador. The shield's glacially scoured surface contains thin soil layers unsuitable for agriculture but holds significant mineral deposits including gold, silver, copper, nickel, iron, and uranium. The region's countless lakes and rivers resulted from glacial scouring during the Pleistocene epoch, which ended approximately 11,700 years ago.
Hudson Bay occupies 1.23 million square kilometres of the Canadian Shield's interior, forming the world's second-largest bay after the Bay of Bengal. The bay reaches a maximum depth of 270 metres and maintains an average depth of 100 metres. Hudson Bay remains frozen for eight to nine months annually, with ice breakup typically occurring in June and freeze-up beginning in November. The bay connects to the Atlantic Ocean through Hudson Strait to the northeast and to the Arctic Ocean through Foxe Basin to the north. Beluga whales, numbering approximately 55,000 individuals, migrate into the bay's estuaries each summer, particularly near the Churchill River mouth in Manitoba.
The Rocky Mountains extend 4,800 kilometres from British Columbia into the United States, forming the eastern boundary of British Columbia's interior. Mount Robson stands as the Canadian Rockies' highest peak at 3,954 metres. The Columbia Icefield, straddling the British Columbia-Alberta border, covers 325 square kilometres and reaches depths exceeding 350 metres. This icefield feeds eight major glaciers including the Athabasca Glacier, which has retreated approximately 1.5 kilometres since 1890 and currently recedes at roughly 5 metres annually. The Continental Divide follows the Rockies' crest, determining whether water flows to the Pacific, Atlantic, or Arctic oceans.
The Great Lakes system contains 21% of the world's surface fresh water, holding 22,810 cubic kilometres. Lake Superior, shared between Ontario and the United States, covers 82,100 square kilometres with a maximum depth of 406 metres, making it the world's largest freshwater lake by surface area. Lake Huron covers 59,600 square kilometres, Lake Michigan lies entirely within the United States, Lake Erie spans 25,700 square kilometres, and Lake Ontario covers 19,000 square kilometres. The lakes formed through glacial processes, with their current configuration established approximately 10,000 years ago. Water flows from Lake Superior through the St. Mary's River into Lake Huron, through Lake Erie via the Detroit River, then into Lake Ontario before exiting through the St. Lawrence River.
The St. Lawrence River extends 1,197 kilometres from Lake Ontario's eastern outlet near Kingston, Ontario, to the Gulf of St. Lawrence. The river's flow rate averages 10,100 cubic metres per second at Quebec City, varying seasonally between approximately 6,800 cubic metres per second in winter and 16,800 cubic metres per second during spring flood periods. The St. Lawrence Seaway, completed in 1959, allows ocean-going vessels to reach Lake Superior through a series of locks and channels. Seven locks between Montreal and Lake Ontario lift vessels 75 metres. The river freezes partially during winter, with ice cover duration at Montreal averaging 92 days annually, though commercial shipping maintains year-round operation through icebreaker assistance.
The Mackenzie River system stretches 4,241 kilometres from Great Slave Lake's western end to its delta on the Beaufort Sea, making it Canada's longest river system and North America's second longest after the Mississippi-Missouri. When measured from its furthest source at the Finlay River headwaters in British Columbia, the total length reaches 4,241 kilometres. The Mackenzie River itself runs 1,738 kilometres from Great Slave Lake to its Arctic Ocean delta. The river's average discharge at its mouth measures 9,700 cubic metres per second, with peak flows reaching 30,000 cubic metres per second during spring breakup in June. The Mackenzie Delta covers 13,000 square kilometres, containing thousands of lakes and channels that freeze solid from October through May.
Great Bear Lake, located on the Arctic Circle at 65 degrees north latitude, covers 31,153 square kilometres, making it the largest lake entirely within Canada and the fourth-largest in North America. The lake reaches depths of 446 metres and contains 2,236 cubic kilometres of water. Ice covers Great Bear Lake from late November through July, with ice thickness reaching 2.4 metres by April. Water temperatures rarely exceed 12 degrees Celsius even during brief summer periods. The lake drains westward through the Great Bear River into the Mackenzie River, with average outflow of 123 cubic metres per second.
The Prairie region extends across southern Manitoba, Saskatchewan, and Alberta, covering approximately 1.8 million square kilometres. This grassland zone occupies the Interior Plains physiographic region between the Canadian Shield to the east and the Rocky Mountains to the west. The prairies divide into three vegetation zones: tall grass prairie with vegetation exceeding one metre in the wetter eastern sections, mixed grass prairie across central zones, and short grass prairie in drier western areas. Glacial deposits during the Wisconsin glaciation, which ended 10,000 years ago, created the region's characteristic flat to gently rolling topography. Fertile chernozemic soils, particularly in the dark brown and black soil zones, cover much of southern Manitoba and Saskatchewan. These soils developed under grassland vegetation over millennia, accumulating organic matter in the top 30 to 60 centimetres.
Baffin Island covers 507,451 square kilometres in Nunavut, making it the world's fifth-largest island after Greenland, New Guinea, Borneo, and Madagascar. The island extends 1,600 kilometres from north to south and reaches 730 kilometres at its widest point. The Baffin Mountains along the eastern coast contain peaks exceeding 2,000 metres, with Mount Odin reaching 2,147 metres. The Barnes Ice Cap on the central plateau covers approximately 6,000 square kilometres, containing ice from the last glacial period. Iqaluit, Nunavut's capital, sits on Baffin Island's southern coast at 63.75 degrees north latitude. The island's population numbered approximately 13,000 in the 2021 census, predominantly Inuit.
The Arctic Archipelago consists of 36,563 islands covering 1.4 million square kilometres north of mainland Canada. Ellesmere Island, the northernmost and third-largest Canadian island, covers 196,236 square kilometres and reaches 83 degrees north latitude at Cape Columbia, only 769 kilometres from the North Pole. The archipelago's islands lie within the Arctic Circle, experiencing continuous daylight from approximately April to August and continuous darkness from October through February at northern latitudes. The Northwest Passage, several possible routes through the archipelago between the Atlantic and Pacific oceans, remains navigable only during brief summer periods in most years. Ice cover duration varies by route and year, with the southern route through Amundsen Gulf typically offering more ice-free days than northern routes.
Vancouver Island extends 460 kilometres along British Columbia's southwestern coast, covering 31,285 square kilometres to rank as North America's Pacific coast's largest island. The island's interior mountain ranges include the Vancouver Island Ranges, with Golden Hinde reaching 2,195 metres as the island's highest point. Heavy orographic precipitation, caused by moist Pacific air rising over the island's mountains, delivers over 6,500 millimetres annually to the island's western slopes, supporting temperate rainforest ecosystems. Victoria, British Columbia's capital, occupies the island's southeastern tip at 48.43 degrees north latitude, making it Canada's most southerly provincial capital.
The Bay of Fundy, separating New Brunswick from Nova Scotia, experiences the world's highest tidal range due to tidal resonance within the bay's funnel shape and 270-kilometre length. The bay's natural oscillation period of 12.4 hours closely matches the 12-hour 25-minute semidiurnal tidal cycle, creating resonance amplification. Maximum tidal ranges reach 16.3 metres at Burntcoat Head, Nova Scotia, while typical ranges measure 14 metres at the Minas Basin's upper reaches. Approximately 100 billion tonnes of seawater flows in and out of the Bay of Fundy twice daily, exceeding the combined flow of all rivers worldwide. Twice-daily tidal cycles expose extensive mudflats containing marine sediments up to 250 metres deep, accumulated over 10,000 years since glacial retreat.
The Niagara Escarpment extends 725 kilometres from Queenston, Ontario, on the Niagara River to Tobermory at the tip of the Bruce Peninsula, then continues underwater to Manitoulin Island and the Upper Peninsula of Michigan. This cliff face, ranging from 15 to 300 metres in height, formed from erosion-resistant Silurian dolomite overlaying softer shales and sandstones. Differential erosion created the escarpment approximately 450 million years ago when the rocks were deposited in a shallow tropical sea. Niagara Falls, located where the Niagara River crosses the escarpment, currently erodes the cliff face at approximately 30 centimetres annually, down from historical rates exceeding one metre yearly before hydroelectric diversion reduced water flow. The Horseshoe Falls on the Canadian side carries approximately 90% of the Niagara River's flow, averaging 2,832 cubic metres per second.
The Appalachian Mountain range extends into southeastern Quebec and the Maritime provinces, representing the northern terminus of a mountain system stretching 2,400 kilometres from Alabama. The Canadian Appalachians, significantly eroded compared to southern sections, reach maximum elevations of 1,268 metres at Mont Jacques-Cartier in Quebec's Gaspésie region. These mountains formed through multiple orogenic events between 480 and 300 million years ago during the Paleozoic era. The Long Range Mountains on Newfoundland's west coast, reaching 814 metres at Lewis Hills, represent the Appalachian system's northeastern extent.
The Fraser River flows 1,375 kilometres from its source near Mount Robson in the Rocky Mountains to the Strait of Georgia near Vancouver. The river drains 220,000 square kilometres, approximately one-quarter of British Columbia's area. Average flow at the river's mouth measures 3,475 cubic metres per second, with peak flows during spring snowmelt reaching 15,600 cubic metres per second. The Fraser delivers approximately 20 million tonnes of sediment annually to its delta, which covers 1,000 square kilometres and continues expanding at roughly 11 hectares yearly. The river remains ice-free throughout winter except in upper reaches, supporting Pacific salmon spawning runs including all five Pacific salmon species. Approximately 50% of North America's sockeye salmon pass through the Fraser River system.
Point Pelee, extending into Lake Erie from the Ontario mainland, reaches 41.9 degrees north latitude at its southern tip, marking Canada's southernmost mainland point. This 20-square-kilometre spit formed through sand deposition from Lake Erie's longshore currents over 10,000 years since glacial retreat. The point's latitude matches northern California and Rome, Italy. Carolinian forest species including black walnut, hackberry, and sycamore grow here at their northern range limits, representing Canada's smallest but most biodiverse forest region. Point Pelee experiences approximately 2,700 growing degree days annually, compared to 1,800 in Toronto 250 kilometres north.
The permafrost zone covers 40 to 50% of Canada's land area, approximately 5 million square kilometres. Continuous permafrost, where over 90% of ground remains frozen year-round, covers regions north of approximately 60 degrees latitude in most areas. The discontinuous permafrost zone, where 50 to 90% of ground remains frozen, extends south to approximately 55 degrees latitude in eastern Canada and 60 degrees latitude in western regions. Permafrost depth varies from 350 to 650 metres in continuous zones. Active layer thickness, the surface layer that thaws annually, ranges from 15 centimetres in far northern regions to 4 metres in southern discontinuous zones. Ground temperature monitoring indicates permafrost warming rates of 0.1 to 0.3 degrees Celsius per decade since 1970 across most monitoring stations.
The Columbia Mountains, distinct from the Rocky Mountains, occupy southeastern British Columbia between the Rockies and the Interior Plateau. This range includes four subranges: the Cariboo, Monashee, Selkirk, and Purcell Mountains. Mount Sir Sandford in the Selkirks reaches 3,519 metres, the highest peak in the Columbia Mountains. These mountains receive heavier precipitation than the Rockies due to moisture from the Pacific Ocean, with some areas receiving over 2,000 millimetres annually. The Selkirk Mountains host the world's only population of mountain caribou, a distinct ecotype numbering fewer than 1,500 individuals across 14 remaining herds.
The Interior Plateau of British Columbia occupies the region between the Coast Mountains to the west and the Columbia Mountains to the east, covering approximately 500,000 square kilometres. Elevations range from 900 to 1,500 metres. This semi-arid region receives 300 to 500 millimetres of annual precipitation, significantly less than surrounding mountain ranges that intercept Pacific moisture. The Cariboo region in the plateau's northern section contains extensive grasslands and mixed forest. The Okanagan Valley in the southern plateau, extending 200 kilometres north-south, contains Canada's only desert conditions, with areas near Osoyoos receiving under 300 millimetres of annual precipitation.
The Coast Mountains extend 1,600 kilometres along British Columbia's Pacific coast from the Fraser River to the Alaska Panhandle. This range reaches maximum elevations of 4,019 metres at Mount Waddington. The Coast Mountains contain the largest concentration of glaciers outside polar regions, with over 6,000 identified glaciers covering approximately 11,000 square kilometres. The Stikine Icecap covers 4,000 square kilometres, while the Juneau Icefield straddles the British Columbia-Alaska border covering 3,900 square kilometres. Orographic precipitation delivers over 4,000 millimetres annually to western slopes, while eastern rain-shadow areas receive under 400 millimetres.
Lake Winnipeg covers 24,514 square kilometres in Manitoba, ranking as the world's 11th-largest freshwater lake by area. The lake extends 416 kilometres north-south with an average width of 100 kilometres. Despite its large surface area, Lake Winnipeg maintains an average depth of only 12 metres and maximum depth of 36 metres, making it extremely shallow. The lake drains 984,200 square kilometres, receiving water from the Saskatchewan River system to the west, the Red River from the south, and the Winnipeg River from the east. Outflow occurs through the Nelson River northward to Hudson Bay, averaging 2,370 cubic metres per second.
The Torngat Mountains occupy northern Labrador and extend into Quebec, reaching maximum elevations of 1,652 metres at Mount Caubvick on the Labrador-Quebec border. These mountains represent the Appalachian system's northeastern terminus, containing some of Canada's oldest exposed rock formations dating to 3.9 billion years ago. Glacial activity during the Wisconsin glaciation carved deep fjords along the coast, with some extending over 30 kilometres inland. The Torngats remain largely unforested due to their northern latitude between 58 and 60 degrees north, supporting Arctic tundra vegetation.
The Laurentian Mountains extend 1,448 kilometres across southern Quebec from the Ottawa River to the Saguenay River. These mountains, part of the Canadian Shield's southern edge, reach maximum elevations of 1,166 metres at Mont Raoul-Blanchard. The range formed through tectonic activity associated with the Ottawa-Bonnechere Graben, a failed rift system active 570 million years ago. Glacial activity created the region's characteristic rounded peaks and numerous lakes. The Laurentians receive 1,000 to 1,200 millimetres of annual precipitation, supporting mixed deciduous and coniferous forests.
The Cypress Hills, straddling the Alberta-Saskatchewan border, reach 1,468 metres elevation at their highest point, standing 600 metres above surrounding prairie. These hills escaped glaciation during the Wisconsin period due to their elevation, creating a biological refugium. The higher elevation supports lodgepole pine forest more typical of Rocky Mountain foothills 400 kilometres west. The hills cover approximately 2,600 square kilometres, with 200 square kilometres protected in provincial parks. Annual precipitation reaches 450 millimetres, higher than surrounding prairies receiving 300 to 350 millimetres.