Because of the land uplift phenomenon the Kvarken archipelago is relatively young. At the beginning of our era not much of what is now archipelago was visible above the surface of water. For this reason, few prehistoric remains can be found in the archipelago, compared with on the mainland, but there is an abundance of historic artefacts dating back to the early forms of livelihood, especially fishing and seal hunting, though wartime remains can also be found.
We do not know when the archipelago had its first permanent population. We have written evidence of permanent settlements from the early fifteenth century and it is likely that this settlement formed long before that time.
Fishing and seal hunting were the principal industries up to the end of the eighteenth century. Most of the male population hunted seals during the winters. A hunting trip could take a few months. The hunters looked for open channels in the ice in which to hunt for seals, but during extremely harsh winters without open channels and with the edge of the ice far to the south in the Gulf of Bothnia, they came home empty-handed. Oil, sealskins, and fish have been important export and barter goods. They fished in every type of water body from the tiniest stream to the open sea. With the long distances home and the boats of that time, it was necessary to temporarily live out on the islands during the fishing trips. At first they built wind shelters by lining up rocks and covering them with something, perhaps a sail. Remains of these shelters have been found on many islands. The first timber-frame fishing cottages were built during the seventeenth century.
Farming was small-scale and focused on raising cattle since the barren soil and the climate limited agriculture. Settlers made use of anything that could be eaten and with the intensive grazing and haying an open landscape developed, completely different from what we see today in the inner archipelago. Even the outer archipelago did not escape the impact of farming. In the fishing villages, fishermen and families of boat pilots and lighthouse keepers often kept a few cows and sheep, and both grazing and agriculture for animal feed were common.
People travelled between the islands and the mainland over Kvarken during both summer and winter. For centuries people traded fish for grain. Traffic appears to have been extremely lively during the seventeenth century and people as well as the mail and goods were transported over the Kvarken straits. The inhabitants of the archipelago, who were familiar with the difficult waters, often had to help out as drivers or boat pilots. In the seventeenth century the shipbuilding and tar-boiling industries also became increasingly important. These industries used the pine forests in the area and benefited the fir, which is now the predominant tree species. Tar-boiling was not particularly significant in the archipelago because there was not much forest.
Major wars between 1714 and 1721 left lasting impressions that can still be seen today. The best known remains are the "Russian ovens", believed to have been built to bake bread and for other cooking and to provide heating. Most of the coastal villages were burnt and plundered, which is why buildings or objects older than this era are seldom found.
Most resources went to reconstruction during the post-war period. In the middle of the eighteenth century the rules for trading changed, and shipbuilding and maritime shipping gained speed. Ostrobothnia led this development. Farming also underwent major changes during this period. Previously, people were both farmers and fishermen; now the mainland farmers began to focus more on agriculture and a category of professional fishers began to evolve. This trend was clearer on the mainland, while as recently as the nineteenth century people were practiced in both livelihoods, side by side.
During the nineteenth century the standard of living rose, the population grew and new side sources of income, such as saltpetre production, iron works and glass-making, grew in importance. The period was also characterised by an increased interest in the natural sciences and people began to wonder about the "decrease in water". Water level marks were cut to calculate how quickly the water was falling, the oldest of which can be found on Ratan (1749) and Rönnskär (1697).
Many more or less spectacular marches have been made across the ice of the Kvarken strait. During the war of 1808-1809, Russian troops marched under the leadership of General Barclay de Tollys across the Kvarken to conquer Umeå. It was cold and the ice conditions were difficult; many horses and hundreds of soldiers were lost during the journey. The general later stated that it was not necessary to mark the route across the Kvarken "because I've done so with the corpses of my soldiers".
The first lighthouse along the western side of Kvarken was built on Holmögadd. It was a coal-burning (vippfyr) lighthouse with a rocker arm, built in 1760. A similar lighthouse was built on Molpehällorna in eastern Kvarken in 1668. In 1848 the first lighthouse was lit on the Finnish side of Kvarken on Norrskär. About 40 years later a lighthouse was built on Valsörarna. In the 1960s this era came to an end when the lighthouses were automated and pilot stations were merged into larger units. In eastern Kvarken the last lighthouse-keeper left his post at the Norrskär lighthouse in 1986. Holmögadd in western Kvarken, which is now a stone lighthouse, was manned until 2005, when the last Swedish lighthouse keeper retired. Piloting is now concentrated to two stations, in Umeå and Vasa.
As the country transitioned to the twentieth century, communications changed and as a result Ostrobothnian coastal towns such as Vasa were no longer central to maritime shipping. At the same time, the traffic across the Kvarken strait, which had been so lively until then, came to an end - in part because of the milder winters, but also because ships had greater capacity.
With the First World War, human smuggling began over the Kvarken strait. Many young men made their way illegally over Kvarken to study military science in Germany in the run-up to the war of liberation against Russia. The Prohibition Act, implemented in 1919, kicked off a wave of smuggling, involving not just alcohol, but other desirable goods such as coffee, cocoa, spices, tin and rubber goods.
During the winter of 1939-1940 the first motorised winter traffic crossed between Vasa and Umeå. The winter war had begun and Finland suffered from supply shortage. The route was open for two months and during that time about 2,000 truckloads were driven over the Kvarken strait, first with clothing and food, and later with munitions. The crossings were often dangerous, yet only one person died, a truck driver whose vehicle sunk. The return loads mainly consisted of cellulose. Since 1947 more or less regular passenger traffic has travelled over the Kvarken strait. In 1958 the first car ferry began service.
The fishing industry underwent a great upheaval during the twentieth century, with mechanisation and the use of synthetics in the equipment. Recreation also entered the picture. The first summer cottages were built close to the cities during the first half of the twentieth century and a construction boom began after the 1960s. Conservation groups, however, reached the outer archipelago first and the impact of recreational activities is only local.