The archipelago extends from Stockholm roughly 60 kilometres (37 miles) to the east. In a north–south direction, it mainly follows the coastline of the Södermanland and Uppland provinces, reaching roughly from Öja island, south of Nynäshamn, to Väddö, north of Norrtälje. It is separated from Åland by a stretch of water named South Kvarken. A separate group of islands lies further north, near the town of Öregrund. Between Arholma and Landsort there are approximately 24,000 islands and islets. Some of the better-known islands are Dalarö, Finnhamn, Nässlingen, Grinda, Husarö, Ingarö, Isö, Ljusterö, Möja, Nämndö, Rödlöga, Tynningö, Utö, Svartsö and Värmdö.
The biggest towns of the archipelago, apart from Stockholm, are Nynäshamn, Vaxholm and Norrtälje. The village of Ytterby, famous among chemists for naming no fewer than four chemical elements (erbium, terbium, ytterbium and yttrium), is situated on Resarö in the Stockholm archipelago.
The shipping routes from the Baltic to Stockholm pass through the archipelago. There are three main entrances suitable for deep-draught craft, namely, those near Landsort, Sandhamn, and Söderarm.
The landscape has been shaped – and is still being shaped – by post-glacial rebound. It was not until the Viking Age that the archipelago began to assume its present-day contours. The islands rise by about three millimeters each year. In 1719 the archipelago had an estimated population of 2,900, consisting mostly of fishermen. Today the archipelago is a popular holiday destination with some 50,000 holiday cottages (owned mainly by Stockholmers). The Stockholm Archipelago Foundation, dedicated to the preservation of the nature and culture of the archipelago, owns some 15% of its total area.
The inhabitants in the archipelago, from around the mid-1400s to the end of the second world war, were combined farmers and fishermen. Spring and autumn fishing was quite intensive in the outer archipelago from 1450 until the mid-1800s, and many fishermen lived for long periods in the outer islands because of the long distances to their permanent houses in the inner archipelago. The combined farming and fishing culture lasted until around 1950–1955 when the younger generation, born during and directly after the war, started to leave the archipelago and look for jobs in the cities on the mainland. Today most of the small farms on the islands are closed and the fishing industry has almost disappeared.
Many poets, authors and artists have been influenced and fascinated by the Stockholm archipelago. Among them are August Strindberg, Ture Nerman, Roland Svensson, Ernst Didring and Aleister Crowley. Björn Ulvaeus and Benny Andersson from the group ABBA wrote most of their songs in a cabin located on the archipelago.
Boating is an extremely popular activity with the sailing race Ornö runt (or Around the island of Ornö) being the largest in the archipelago. This annual race, organised by the Tyresö Boat Club, has taken place every year since 1973. It is open to anyone with a sailing boat but requires registration. There are different entry classes, with the family class being the least competitive.
In the winter skaters make excursions over the ice.
Visiting the larger islands in the archipelago is easy all year round, but during winter period the routes depend on the ice conditions. Several companies have regular routes. The largest ship owner company is Waxholmsbolaget owned by the Stockholm County government. Taxi boats are also available. In summer the archipelago bristles with private boats filled with people who often take advantage of Allemansrätt (or "everyman's right"), a law which gives anyone the right to go ashore or anchor on any ground not in the direct vicinity of buildings.