The largest lake in the world is the Caspian Sea, which covers about 371,000 km² (143,000 sq mi) between Russia, Kazakhstan, Turkmenistan, Iran and Azerbaijan. Second is Lake Superior on the Canada–United States border at 82,100 km², and third is Lake Victoria in East Africa at about 59,940 km². The rest of the top ten by surface area, following the figures used on Wikipedia’s list of lakes by area, are Lake Huron, Lake Michigan, Lake Tanganyika, Lake Baikal, Great Bear Lake, Lake Malawi and Great Slave Lake. Five of the ten sit in North America, three in Africa’s Great Lakes region and two in Russia or on its border, and two of the rankings depend on definitions that geographers still argue about.
The Top Ten Lakes by Surface Area at a Glance
Lake areas are not fixed. Salt lakes in dry basins swell and shrink, and even the big freshwater lakes are measured slightly differently by different agencies, so the figures below are the ones given in Wikipedia’s list of lakes by area and the individual lake articles, except that the Caspian is shown without its Garabogazköl lagoon. Reservoirs such as Lake Volta and seasonal lakes such as Kati Thanda–Lake Eyre in Australia are left out, because they are either man-made or dry for much of the time.
| Rank | Lake | Area (km²) | Countries |
|---|---|---|---|
| 1 | Caspian Sea | 371,000 | Russia, Kazakhstan, Turkmenistan, Iran, Azerbaijan |
| 2 | Lake Superior | 82,100 | Canada, United States |
| 3 | Lake Victoria | 59,940 | Tanzania, Uganda, Kenya |
| 4 | Lake Huron | 59,570 | Canada, United States |
| 5 | Lake Michigan | 57,800 | United States |
| 6 | Lake Tanganyika | 32,900 | Tanzania, DR Congo, Burundi, Zambia |
| 7 | Lake Baikal | 31,722 | Russia |
| 8 | Great Bear Lake | 31,153 | Canada |
| 9 | Lake Malawi | 29,600 | Malawi, Mozambique, Tanzania |
| 10 | Great Slave Lake | 27,200 | Canada |
The chart makes the main point plainly: the Caspian is in a class of its own, then comes a cluster of four lakes between about 58,000 and 82,000 km², and then a second cluster of five lakes between 27,000 and 33,000 km². Below tenth place the drop continues gently, with Lake Erie at 25,667 km², Lake Winnipeg at 24,514 km² and Lake Ontario at 19,011 km².
10 to 8: Great Slave, Malawi and Great Bear
10. Great Slave Lake (27,200 km²). The second-largest lake in Canada’s Northwest Territories is also the deepest lake in North America, reaching 614 m (2,014 ft). It is 469 km long, and Yellowknife, the territorial capital, stands on its north shore. Like Great Bear Lake and Lake Athabasca, it is a remnant of the vast glacial Lake McConnell. Its main western bowl is under 190 m deep, while the island-filled East Arm, at the edge of the Canadian Shield, holds the 614 m maximum in Christie Bay. The lake takes its name from the Dene people whom the Cree called Slavey.
9. Lake Malawi (29,600 km²). Known as Lake Nyasa in Tanzania and Lago Niassa in Mozambique, this is the southernmost lake of the East African Rift, between 560 and 580 km long and 706 m deep at its deepest point. Its size is the product of rifting: the crust is pulling apart, and the lake fills the long trench between the escarpments. It holds more fish species than any other lake on Earth, including at least 700 species of cichlid, and part of it is protected as Lake Malawi National Park.
8. Great Bear Lake (31,153 km²). Straddling the Arctic Circle in the Northwest Territories, Great Bear is the largest lake lying entirely inside Canada. Its basin was gouged by glaciers, and it is covered with ice from late November until July. The explorer John Franklin wrote in 1828 that a white rag lowered into its water stayed visible to about 27 m. The name comes from a Chipewyan word meaning “grizzly bear-water people”, and the Sahtu Dene take their name from the lake.
7 and 6: Baikal and Tanganyika, the Deep Rift Lakes
7. Lake Baikal (31,722 km²). In southern Siberia, between Irkutsk Oblast and the Republic of Buryatia, Baikal is only seventh by area, slightly larger than Belgium, but no other lake comes close to it underneath. It reaches 1,642 m (5,387 ft), the deepest lake on Earth, and holds about 23,600 km³ of water, roughly 22–23% of the world’s fresh surface water and more than all five North American Great Lakes together. It sits in an active rift that has been opening for 25–30 million years, which also makes it the oldest lake known. UNESCO listed it as a World Heritage Site in 1996.
6. Lake Tanganyika (32,900 km²). The Albertine Rift, the western branch of the East African Rift, holds the world’s longest freshwater lake: 676 km from north to south but only about 50 km wide on average. Four countries share it, with Tanzania holding about 46% and the Democratic Republic of the Congo about 40%, and Burundi and Zambia the rest. It is the second-deepest lake after Baikal at about 1,470 m, the second-largest by volume, and drains west through the Lukuga River into the Congo. At least 250 cichlid species live only here. If you are more interested in depth than in surface area, these two rift lakes lead the list of the deepest lakes in the world.
5 to 3: Michigan, Huron and Victoria
5. Lake Michigan (57,800 km²). The only Great Lake wholly inside the United States is shared by Wisconsin, Illinois, Indiana and Michigan, with Chicago, Milwaukee and Green Bay on its shores. That makes it the largest lake by area inside a single country. Its name is thought to come from the Ojibwe mishigami, “great water”.
4. Lake Huron (59,570 km²). Shared by Ontario and Michigan, Huron includes Georgian Bay and the North Channel, and Manitoulin Island in its north is the largest island in any lake. Here comes the first definitional problem. Huron and Michigan are joined by the Straits of Mackinac, which are about 8 km wide, and the two share one water level. Hydrologically they are a single body, Lake Michigan–Huron, and on that reckoning their combined area of roughly 117,000 km² would make it the largest freshwater lake in the world, ahead of Superior. By convention, though, they are counted as two lakes.
3. Lake Victoria (59,940 km²). Africa’s largest lake and the world’s largest tropical lake fills a shallow basin between the two arms of the East African Rift rather than a rift trench, so it is broad but only about 80 m deep at most. Tanzania holds 49% of its surface, Uganda 45% and Kenya 6%. Its shoreline runs to about 7,142 km when mapped in detail. The local names include Nam Lolwe in Dholuo and Nnalubaale in Luganda; the English name was given by John Hanning Speke, the first Briton to document the lake, in 1858. The introduced Nile perch has driven many of its native cichlids to extinction. The site’s guide to the largest lakes in Africa covers Victoria, Tanganyika and Malawi together.
Number 2: Lake Superior and Its 12,100 km³ of Water
Lake Superior is the largest freshwater lake in the world by surface area when Michigan and Huron are counted separately. It covers about 82,100 km², roughly the size of Austria, and straddles the border between Ontario to the north and the states of Minnesota, Wisconsin and Michigan to the south. It is 563 km long and 257 km wide at its maximum, reaches 406 m in depth, and holds about 12,100 km³ of water, more than the other four Great Lakes combined.
Superior owes its size to the Midcontinent Rift, a failed split in the North American plate whose basalt still forms Isle Royale and Michipicoten Island, and then to repeated glaciation, which deepened the basin. The Ojibwe name, gichi-gami, means “great sea”, and the lake behaves like one. The stretch between Grand Marais and Whitefish Point is called the Graveyard of the Great Lakes, and the SS Edmund Fitzgerald sank about 28 km from Whitefish Point on 10 November 1975 with all 29 crew. The cold water, under 2 °C on average around 1970, slows decay so much that bodies rarely surface.
Number 1: the Caspian Sea, Lake or Small Ocean?
The Caspian Sea covers about 371,000 km², an area similar to Japan, if the shallow, highly saline Garabogazköl lagoon on its eastern side is left out. Wikipedia’s lake list counts the lagoon in and gives about 389,000 km². Either way, it is more than four times the size of Superior. It stretches about 1,200 km from north to south, its surface lies about 27 m below sea level, and its southern basin reaches about 1,025 m deep. Its water is about 1.2% salt, roughly a third of the salinity of the ocean, and its main inflow is the Volga, Europe’s longest river, which enters at the shallow northern end.
Two arguments surround it. The first is geological. Every other lake on the list lies on continental crust, but the Caspian’s southern basin is floored by oceanic crust, a remnant of the ancient Tethys Ocean, which is why some geologists class it as a small ocean. On that definition, Michigan–Huron becomes the largest lake on Earth. The second argument is legal. Whether the Caspian counts as a sea or a lake under international law changes how the five shoreline states divide its seabed and its oil and gas, and after negotiations that ran from about 1990, the five leaders signed the Convention on the Legal Status of the Caspian Sea at a summit in Aktau, Kazakhstan, on 12 August 2018. The site’s full guide to the Caspian Sea covers its oil fields, caviar sturgeon and falling water level, which could drop by 9–18 m this century as the climate warms and inflows fall.
Whichever definition you choose, the order below it is stable: Superior, Victoria, Huron, Michigan and Tanganyika lead the freshwater lakes by area, while Baikal, only seventh by area, holds more water than any of them.