Why does Finland have so many lakes?

Because of the last ice age. The ice sheet scoured hollows into the bedrock and left behind moraines and eskers that dammed water. When the ice melted about 10,000 years ago, the hollows filled with water.

What is the Saimaa ringed seal?

A rare freshwater subspecies of ringed seal found only in Lake Saimaa. Its ancestors were cut off from the sea after the ice age. It is endangered, with a population that recent counts put in the hundreds.

A long, narrow ridge of sand and gravel left by a meltwater river that flowed under or inside a glacier. In Finnish it is called a harju, and Punkaharju is the best-known example.

Is there midnight sun in the Finnish Lakeland?

Not quite. The Lakeland lies south of the Arctic Circle, so the sun sets briefly at midsummer, but the sky stays light all night. These bright summer nights are called white nights.

Can I explore the Finnish Lakeland in the app?

Yes. You can land in a Lakeland scene modelled on Lake Saimaa and Koli and explore its lakes, islands and forested ridges in interactive 3D.

A maze of blue water, forested islands and glacial ridges under the white nights

Finnish Lakeland

3D landscape · Koli, North Karelia, Finland

Land here and explore →

Finland is often called the land of a thousand lakes, but the real number is far higher: a commonly quoted count is around 188,000 lakes larger than 500 square metres. The greatest concentration lies in the Lakeland of eastern and central Finland, where water, islands, peninsulas and forested ridges interlock so closely that it can be hard to tell where one lake ends and the next begins. In this app you can land in a Lakeland scene modelled on Lake Saimaa and the hills of Koli and explore it in interactive 3D.

The Lakeland is a young landscape. Only around 10,000 to 11,000 years ago this whole region lay under a thick ice sheet, and the lakes fill hollows and channels shaped by the ice and its meltwater. Today it is a place of quiet water and boreal forest, of the haunting calls of divers on summer evenings, of light that barely fades at midsummer, and of countless summer cottages, each with its sauna by the shore.

Key facts

Model setting: Lake Saimaa and KoliEastern Finland, in the regions of South Savo, North Karelia and South Karelia
Lakes in Finland: About 188,000A widely quoted count of lakes larger than 500 m²
Largest lake: SaimaaUsually given as around 4,400 km² in total, including connected basins
Islands in Saimaa: Roughly 14,000Figures vary with how small an island is counted
Rare resident: Saimaa ringed sealEndangered and found only in Lake Saimaa
Origin: Last ice ageThe ice retreated from the region roughly 10,000–11,000 years ago
Famous esker: PunkaharjuA narrow gravel ridge running between lakes near Savonlinna
Koli National Park: Founded 1991Overlooking Lake Pielinen in North Karelia
Sauna culture: UNESCO-listed in 2020Inscribed on the Representative List of the Intangible Cultural Heritage of Humanity

Why there are so many lakes

Finland's lakes are a gift of the ice age. During the last glaciation, an ice sheet up to two or three kilometres thick covered Scandinavia and Finland. As it slowly flowed across the land, it scraped away loose soil and gouged hollows and grooves into weaker zones of the ancient bedrock. Much of the Lakeland's pattern, with long lakes and peninsulas aligned roughly north-west to south-east, follows the direction of ice flow and lines of weakness in the rock.

When the climate warmed and the ice melted back, it left a jumble of debris. Moraines, heaps of rock, sand and clay dumped by the ice, blocked valleys and dammed water. The great Salpausselkä ridges, which curve across southern Finland, formed at the edge of the ice during a cold pause more than 11,000 years ago and act as a natural barrier along the southern rim of the Lakeland. Countless smaller hollows filled with meltwater and rain to become lakes, ponds and bogs.

Eskers: rivers of gravel

Eskers, called harju in Finnish, are long, winding ridges of sand and gravel laid down by meltwater rivers flowing in tunnels under or within the ice. When the ice disappeared, the riverbeds were left standing as ridges. They often run between lakes like natural causeways, and roads and railways follow them. Punkaharju near Savonlinna is the most famous example.

Post-glacial rebound and shifting waters

The weight of the ice pressed the Earth's crust down, and since the ice melted the land has been slowly rising again. This post-glacial rebound continues today, fastest along the coast of the Gulf of Bothnia, where the land rises by several millimetres a year. In the Lakeland the uplift is slower, but because the land rises more in the north-west than in the south-east, the whole region has been gradually tilting.

This tilting has rearranged the lakes over thousands of years. Water levels rose at the south-eastern ends of basins until, in places, lakes broke through ridges and found new outlets. Lake Saimaa once drained north-west, but several thousand years ago, often dated to around 6,000 years ago, its waters broke through the Salpausselkä ridge and created the Vuoksi river, which today carries Saimaa's water south-east to Lake Ladoga in Russia.

Lake Saimaa: a labyrinth of islands

Saimaa is Finland's largest lake and one of the largest natural freshwater lakes in Europe. It is not a single open expanse but a maze of connected basins, narrow straits, bays and islands, with a very long, intricate shoreline. Towns such as Lappeenranta, Savonlinna and Mikkeli sit on its shores, and the medieval castle of Olavinlinna stands on an island in Savonlinna.

For centuries the lake was a highway. Timber was floated across it, steamboats linked lakeside towns, and the Saimaa Canal, opened in the nineteenth century, connects the lake to the Gulf of Finland. Today Saimaa is a holiday landscape of cottages, kayaking routes and lake cruises, and parts of it are protected in Linnansaari and Kolovesi national parks.

The Saimaa ringed seal and the black-throated diver

The Saimaa ringed seal is one of the rarest seals in the world and lives nowhere else. Its ancestors were ringed seals of the sea, which became trapped as the land rose after the ice age and Saimaa was cut off from the Baltic, several thousand years ago. Over time they became a distinct subspecies, adapted to fresh water. The population fell to perhaps a couple of hundred animals in the late twentieth century, because of hunting, fishing nets and disturbance. Protection has helped numbers recover slowly, and recent counts by Metsähallitus put the population in the hundreds, but it remains endangered.

Female seals give birth in late winter in lairs dug into snowdrifts on the lake ice, which shelter the pups from cold and predators. Milder winters with less snow threaten this, so in poor snow years people pile up artificial snowdrifts along the shores to help the seals. Restrictions on certain fishing nets in spring and early summer also protect young seals. On summer evenings the Lakeland's other famous voice is heard: the long, eerie wailing of the black-throated diver, called kuikka in Finnish and known in North America as the Arctic loon, carrying across the still water.

White nights, cottages and sauna

Around midsummer, the Lakeland enjoys the white nights. The Lakeland lies south of the Arctic Circle, so the sun does set, but only briefly and not far below the horizon, and the sky stays light through the night. Midsummer, or Juhannus, is one of Finland's biggest celebrations, traditionally marked with bonfires by the water, and many Finns spend it at a summer cottage.

The mökki, or summer cottage, is a central part of Finnish life. There are roughly half a million of them in Finland, many on lake shores, ranging from simple cabins without running water to modern holiday homes. Almost every one has a sauna. Bathing in the heat, throwing water on the stove to make steam, called löyly, and cooling off with a swim in the lake is an everyday ritual. Finnish sauna culture was added to UNESCO's list of intangible cultural heritage in 2020.

Koli and the Lakeland in winter

Koli, in North Karelia, rises above Lake Pielinen as a group of quartzite hills, the worn-down roots of a mountain range that formed around two billion years ago. Its highest point, Ukko-Koli, stands about 347 metres above sea level, high for Finland. The view over lakes, islands and forest inspired painters, writers and composers of the late nineteenth century, including Eero Järnefelt and Jean Sibelius, and became a symbol of Finnish national identity. Koli became a national park in 1991 and is one of Finland's officially designated national landscapes, as is the Punkaharju esker.

In winter the Lakeland changes completely. The lakes usually freeze over from around late autumn or early winter until spring, though freezing and thaw dates vary greatly from year to year, and the ice season is tending to get shorter as the climate warms. Once the ice is thick enough, people ski, skate and fish through holes on the lakes, some ice roads open, and saunas are followed by a dip in a hole in the ice, called avanto. Thin or uneven ice is dangerous, so locals check conditions carefully before going out.

Surprising facts about Finnish Lakeland

Finland has around 188,000 lakes larger than 500 square metres, far more than the famous thousand.
Saimaa's ringed seals are descended from sea seals trapped in the lake after the ice age.
In poor snow years, people build artificial snowdrifts on the ice so that Saimaa seals can make their birth lairs.
The land in Finland is still rising after being pressed down by the ice sheet, slowly tilting the lakes.
Long gravel ridges between the lakes are the beds of rivers that once flowed inside the ice sheet.
Finland has roughly half a million summer cottages, and Finnish sauna culture is recognised by UNESCO.

Frequently asked questions

Why does Finland have so many lakes?: Because of the last ice age. The ice sheet scoured hollows into the bedrock and left behind moraines and eskers that dammed water. When the ice melted about 10,000 years ago, the hollows filled with water.
What is the Saimaa ringed seal?: A rare freshwater subspecies of ringed seal found only in Lake Saimaa. Its ancestors were cut off from the sea after the ice age. It is endangered, with a population that recent counts put in the hundreds.
What is an esker?: A long, narrow ridge of sand and gravel left by a meltwater river that flowed under or inside a glacier. In Finnish it is called a harju, and Punkaharju is the best-known example.
Is there midnight sun in the Finnish Lakeland?: Not quite. The Lakeland lies south of the Arctic Circle, so the sun sets briefly at midsummer, but the sky stays light all night. These bright summer nights are called white nights.
Can I explore the Finnish Lakeland in the app?: Yes. You can land in a Lakeland scene modelled on Lake Saimaa and Koli and explore its lakes, islands and forested ridges in interactive 3D.

Keep exploring

The landscapes in Ember’s Universe are procedural 3D scenes modelled on real places. The landforms, plants and light follow the real thing, but the details are generated, not mapped.

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