Stockholm Archipelago

The Stockholm Archipelago is the largest archipelago in Sweden. It is also the second-largest archipelago in the Baltic Sea. The largest one is the Archipelago Sea, located in Finland. This vast area covers approximately 1,700 square kilometers. Of this total area, about 530 square kilometers is made of land.

This historical map provides a glimpse into how these islands were viewed in the past.

The geography of the archipelago is shaped by a process called post-glacial rebound. This means the land is still rising after the weight of ancient glaciers was removed. The islands rise by about three millimeters every year. This geological movement has continued since the Viking Age. During that era, the islands began to take on their modern shapes. Because the land is moving, the archipelago is a joint valley landscape that is constantly changing.

Water characteristics vary significantly throughout the region. The pH value of the water is neutral at 7.0 or slightly lower. This is different from typical seawater, which has a pH of about 8.0. In the inner parts, humic substances can cause the water to appear brownish. The salinity, or salt content, also changes based on location. In the outer parts, the salinity is around 0.6 to 0.7 percent by weight. This is much lower than proper oceanic water, which is 3.0 percent or more. In the inner parts, sea ice forms regularly every winter.

The archipelago contains a massive number of landforms. There are slightly over 24,000 islands, islets, and skerries between Arholma and Landsort.

Some well-known islands include Värmdö, Grinda, and Utö. The area extends from Stockholm toward the east. It follows the coastlines of the Södermanland and Uppland provinces. It reaches from Öja island in the south to Väddö in the north. The archipelago is separated from Åland by a stretch of water called the South Kvarken.

Human history in the archipelago has shifted from industry to leisure. From the mid-1400s until the mid-1950s, inhabitants were mostly farmers and fishermen. Fishing was very intensive during the spring and autumn seasons. In 1719, the population was only about 2,900 people. Today, the population structure is very different. There are roughly 10,000 permanent residences. However, there are about 50,000 holiday homes, many owned by people from Stockholm. The fishing industry has almost disappeared as the younger generation moved to mainland cities for work.

Travel and connectivity define life in the islands. Some larger islands near the coast, like Vaxholm and Ingarö, have fixed bridges. These islands are connected to road ferries or local bus services. Other islands, such as Möja and Utö, require passenger ships with fixed itineraries. The largest company serving these routes is Waxholmsbolaget.

This image shows a vessel navigating the waters near the islands. Visitors can also use taxi boats to move around. A law called Allemansrätt, or "everyman's right," allows people to anchor or go ashore on most land not near buildings.

The archipelago holds great cultural and scientific significance. The village of Ytterby on Resarö is famous in the field of chemistry. It is where four chemical elements—erbium, terbium, ytterbium, and yttrium—were named. Many artists and writers, such as August Strindberg, have been inspired by the landscape. Even members of the group ABBA wrote songs in an archipelago cabin. Boating is a major activity, including the Ornö runt sailing race. This large annual race has been held every year since 1973. Additionally, parts of the archipelago have been protected as a Ramsar site since 1989.