Åland's geography: an archipelago still climbing out of the Baltic

How much of Åland is actually water

Statistics and Research Åland, the islands' statistics office, known as ÅSUB, put the total area of Åland at 13,325 km² on 1 January 2026. Of that, 11,769 km² was water and 1,556 km² was land. Sea and lakes make up about 88% of the area inside the boundary. The land makes up the other 12%.

The water figure is an administrative quantity. ÅSUB notes under its table of nature reserves that Åland's water area was changed in 2003, and the reserve shares before and after that year are measured against different totals. The boundary itself is written in law. Section 2 of the Act on the Autonomy of Åland defines Åland as the territory it had when the act entered into force, together with the territorial waters directly adjacent to its land, drawn according to the Finnish enactments on the limits of territorial waters. The land is fixed at a date and the sea follows a rule.

The land figure has more versions than the total. ÅSUB's 1,556 km² for 1 January 2026 sits beside 1,553 km² in the English Wikipedia article on the geography of Åland, 1,527 km² in the geography section of the main Åland article and about 1,580 km² in that same article's introduction, where it is given as 0.51% of Finland's land area. The spread between the highest and the lowest is 53 km², a little over 3% of the land. Part of it is definition, which shorelines and which rocks are counted. Part of it is that the shoreline moves.

The main island shows the problem at its sharpest. Fasta Åland is estimated at 740 km², at 879 km² and at over 1,010 km², depending on what is included. Eckerö, Lemland and Lumparland are separated from it and from each other by narrow shallow straits, and they are joined to it by bridges and dikes, so they are usually treated as parts of the main island. The Government of Åland's climate report of 2014 gave Fasta Åland as 70% of the total land area. About 90% of the population lives on it.

Why the count of Åland's islands keeps changing

ÅSUB's 2026 edition of Åland in Figures counts 6,757 islands larger than a quarter of a hectare, about 20,000 smaller than that, and about 60 that are inhabited. The same threshold applied to fresh water gives 379 lakes over a quarter of a hectare and about 1,500 below it. The quarter hectare decides the answer. Drop it and the number of islands roughly quadruples.

Other published counts use other thresholds, or none that they state. NASA's Earth Observatory, describing a Landsat 5 image of the islands taken on 4 June 2011, wrote of several large islands and roughly 6,500 small isles, many of them too small for anyone to live on. The World Autonomies survey of territorial autonomies gives about 6,500 islands and skerries. The English Wikipedia describes nearly 300 habitable islands, 60 to 80 of them inhabited, and more than 6,000 skerries and bare rocks.

That last figure has a history. When Sweden and Finland both claimed Åland in 1919, Finland argued that the islands were historically and geographically linked to it, and Sweden pointed to the islanders' wish to join Sweden. The two sides drew the archipelago differently. Swedish maps concentrated on the main island and played down the skerries around it, which made Åland look closer to Sweden. Finnish maps showed more small islands and drew them larger, which stressed their continuity with the Finnish archipelago to the east. The popular figure of "over 6,000" skerries, repeated since the arbitration, was shaped by that contest of maps.

The maps were argued over again in 2012, this time for their names. The Government of Åland and the islands' business community asked the Finnish land survey to print Åland's place names on its maps in Swedish only, on the ground that Åland is officially monolingual. The survey kept the Finnish names, and a study of Ålandic newspapers from the University of Jyväskylä records the argument that followed in the local press.

What the ice sheet left on Åland's granite

The rock under Åland is red and pink rapakivi granite, peppered with quartz crystals, and it breaks the surface on nearly every island. NASA's Earth Observatory places its formation in the Proterozoic, far earlier than the ice that later shaped its surface.

That ice covered Scandinavia and the Gulf of Bothnia about 20,000 years ago in NASA's account. The History of Åland article on Wikipedia places the Weichselian ice sheet over the region around 18,000 BC and dates its retreat from Åland to about 9000 BC. By 8000 BC the highest peaks of the archipelago stood above the Baltic. The level of the Baltic moved as its basin changed, but no land bridge ever joined Åland to a mainland, and the first people reached the islands by boat or across seasonal ice. People of the Comb Ceramic culture began settling Åland about 7,000 years ago, after the land had started to rise from the sea.

The ice wore the granite smooth and took most of the soil with it. What remains is thin, and shell beds on many of the islands have noticeably raised its fertility. The coast is deeply indented by bays and fjords. A British Foreign Office handbook of 1920 on the islands, whose text the Wikipedia geography article still carries, described them as sheltered harbours for vessels drawing no more than 19 feet, and noted local clay dug for tile and brickworks.

The relief the ice left is low. The highest point is Orrdalsklint in Saltvik. This site's record gives it as 127 m. ÅSUB's 2026 figures and the Government of Åland's 2014 report both give 129 m, and the Wikipedia geography article gives 129.1 m. The same 2014 report mapped the ground lying less than 5 metres above the sea as a category of its own, because along the coast so much of it does.

Why Åland is still rising from the sea

The ice pressed the crust down, and the crust is still recovering. Post-glacial rebound lifts the land by several millimetres a year and gradually adds to the islands' land area. The environment office of the Government of Åland, in a climate adaptation report dated 10 October 2014, put the uplift at about 0.30 to 0.40 metres per hundred years.

That rise is how the archipelago came to exist at all, and it is the reason every count in the section above carries a date. Land that climbs adds area at the shore, and a skerry below the quarter-hectare line in one survey can sit above it in a later one.

The same report set the uplift against the sea. It cited the IPCC's projection of a rise in sea level of 0.52 to 0.98 metres by 2100, noted that climate research then named 2 metres as an upper bound, and tabulated semi-empirical studies whose projections for 2100 ran from 89 cm in Horton and others in 2008 to 190 cm in Vermeer and Rahmstorf in 2009. The Swedish Meteorological and Hydrological Institute expected the mean level of the Baltic to settle 10 to 20 cm above the world ocean average; Finnish projections put it slightly below. The report's conclusion sat under a heading that translates as "a higher sea level despite land uplift": once the uplift is subtracted, Åland should plan for a net rise of up to 60 cm or more.

The islands emerged because the land rose faster than the Baltic did. In the government's own projection of 2014, the sea overtakes that rise within the century.

The report named what that means on the ground. Areas lower than 3 metres above the sea are treated as at risk, with the 5-metre line affected over a longer horizon. It listed changed groundwater levels, salt water entering wells and water supply, erosion and landslips, and local flooding when high water meets storms. It singled out Åland's relatively extensive low-lying coastal areas, and it named sea level, with runoff and inflow, as one of the three factors that set the level of Åland's lakes.

Where Åland meets Sweden and Finland

To the west, Fasta Åland is separated from the Roslagen coast of Sweden by 38 km of open water, the Sea of Åland. The international border runs through it and is clearly defined; the World Autonomies survey dates it to an agreement between Sweden and Russia in 1810. Åland's only land border lies on Märket, an uninhabited skerry that it shares with Sweden. To the north is the Bothnian Sea, and the islands lie across the entrance to the Gulf of Bothnia.

To the east there is no such gap. The Åland archipelago continues into Åboland and the Archipelago Sea off Turku, and Britannica describes the Turku archipelago merging with the Åland Islands in the west. The line on that side is an administrative border within Finland, and it runs through a continuous scatter of rock. Open water on one side and unbroken rock on the other was the asymmetry the maps of the dispute were drawn to argue over, each side emphasising the half that suited its case.

From Mariehamn the ferry distance is about 160 km to Turku on the Finnish mainland and about the same to Stockholm. The Åland Islands Peace Institute describes the demilitarised and neutralised zone as reaching three nautical miles from land, and says it is usually drawn as a cloud around the islands.

Ships reach Åland at three main points. The Western Harbour lies in Mariehamn, Berghamn in the west and Långnäs on the eastern shore of the main island. ÅSUB counted 6,837 arriving vessels in 2025: 3,070 at Mariehamn, 2,719 at Långnäs and 1,048 at Eckerö. Visit Åland attributes Mariehamn's growth to its position close to the main fairway between Sweden and Finland and to good harbours on both sides of the town.

How the Baltic sets Åland's seasons

Åland has a humid continental climate, Dfb in the Köppen classification, strongly tempered by the sea around it. Summers are cooler than on the mainlands of Sweden and Finland, and winters are slightly milder than in the neighbouring parts of Finland.

What the station records show

ÅSUB gives a mean annual temperature of 6.5 °C for the reference period 1991 to 2020 and 7.8 °C for 2025. February is the coldest month in the normal, at minus 2.4 °C, and July the warmest, at 17.0 °C. Precipitation averages 628 mm a year, and the wettest months fall in late summer and autumn, while spring is the driest part of the year.

Sunshine in 2025 ran from 22 hours in December to 298 in July, and at midsummer the sun rises at about half past three in the morning and sets at about ten at night.

The longer record points one way. The annual mean in Mariehamn rose by about half a degree over the twentieth century, according to Göran Stenlid's account of Åland's weather in the twentieth century, which the 2014 report cites. The report also quoted an ÅSUB series in which the annual mean rose from 5.2 to 6.6 °C between 1977 and 2014, and cautioned that the rise of 1.4 degrees was somewhat inflated because too few cold winters fell in the period. At sea, the day the ice breaks up moved about 15 days earlier over 50 years, and the salinity measured off southern Äppelö in northwestern Åland fell from 6.2 to 5.7 parts per thousand between 1991 and 2007.

What the climate projections expect

The 2014 report expected the annual mean on Åland to rise by 2 to 5 degrees by 2100, precipitation to increase by about 10 to 30%, mostly in the winter half of the year, and ice-free winters to become more common. It gave the average extent of Baltic ice as about 204,000 km² and expected a warming of about 3 degrees to cut that by 100,000 to 140,000 km². Grey seals, which mostly give birth on the ice, were among the populations it expected to be affected.

What grows on Åland's thin soils

ÅSUB divides Åland's land surface into forest, 70%, farmland, 13%, built-up ground, 6%, with bare rock and wetland making up the remainder. NASA's description of the 2011 image reads the same way from above: pine and deciduous forest, meadows and farmed fields, and the red granite showing through on nearly every island.

The mild climate supports a fuller vegetation than on mainland Finland. Pine, fir, birch, aspen, elm, ash and lime grow on the islands, and oak occurs in small woods all over Åland. The Government of Åland's environment pages describe a range that runs from forests, wooded meadows and pastures to the bare rocks of the outer archipelago. The meadows and pastures carry many insects, among them the Glanville fritillary butterfly. Elk and other deer were introduced in the twentieth century and are not native.

Seabirds nest on the outer rocks. Migratory birds were traditionally hunted while the native seabirds were protected and their eggs eaten, and the islets of Lågskär and Signilskär held colonies of eider, whose down was gathered from the nests for export after the young had left.

Farming continues on the thin soil. ÅSUB recorded 13,700 hectares of arable land and 319 active farms in 2025, which produced 5,900 tonnes of wheat, 6,090 tonnes of onions and 5,530 tonnes of apples that year. Roundwood production reached 203,000 m³ in 2025, and timber was historically exported for shipbuilding. Fishing is almost entirely one kind: Baltic herring and sprat made up 7,369 tonnes of a total catch of 7,580 tonnes in 2025.

Nature reserves covered 3,729 hectares of land, 2.4% of Åland's land area, and 40,530 hectares of water in 2025, against 616 hectares of land and 6,292 hectares of water in 1980. Access to all of it runs under the right of public access, which the Government of Åland notes differs slightly on Åland from the rules in Sweden and in the rest of Finland.

How Ålanders settled the main island and the archipelago

ÅSUB divides Åland into three kinds of place: Mariehamn, the town; a rural district of nine municipalities on and around the main island; and an archipelago of six municipalities spread across the eastern islands. The balance between them has shifted one way since 1980.

Most of the growth is in the rural district. Jomala went from 2,615 people in 1980 to 5,817 at the end of 2025. Lemland rose from 954 to 2,139 over the same years. In the archipelago, Kumlinge fell from 454 to 271, Kökar from 304 to 211 and Sottunga from 149 to 101. Vårdö is the exception in the archipelago, up from 387 to 465. Density across Åland rose from 15.4 people per km² in 1980 to 19.8 in 2025.

What connects the pieces is road on the main island and ferry everywhere else. Four highways lead to Eckerö, Sund, Lumparland and Geta, and public roads reached 1,096 km in 2025, 983 km of them paved, against 888 km in 1980. Local road and ferry traffic is a competence of the Government of Åland. The archipelago ferries carried 1,008,000 passengers and 661,000 vehicles in 2025, against 930,000 and 441,000 in 1990.

The archipelago holds a far larger share of Åland's summer cottages than of its people. ÅSUB counted 8,565 cottages in 2025, and 31.0% of them stood in the archipelago, against 67.9% in the rural district and 1.1% in Mariehamn; the archipelago's 1,990 residents were about 6% of the population that year.