Björnholmen, Islet in Lake Mälaren, Ekerö Municipality, Sweden

Björnholmen is an island in Lake Mälaren situated within the Drottningholm estate region. It serves as a seasonal retreat with six private residences, operating without electrical connections or modern utilities.

Björnholmen had year-round residents from the 1600s, and in the 1700s a sea tavern operated on the island. Around 1859 the newspaper publisher Franz Sjöberg built the Italian-style Stora Villan, which he lost to creditors two years later. Court president Henrik Wilhelm Bredberg bought it in the 1870s, and his family spent summers there until the 1960s.

According to legend, the islet takes its name from a bear shot here by King Charles IX. In the 18th century a sea tavern (sjökrog) served travellers, and in the first half of the 19th century wealthy Stockholmers came out for day trips. Since the 1950s no one has lived here year-round; six families use the buildings as holiday homes.

Access to the island is limited since it serves as private residences for seasonal use. Visitors should arrange permission in advance, as the absence of utilities and modern facilities means conditions are basic and require preparation.

The name comes from a legend that King Karl IX shot a bear on the island. The island has appeared under this name on every available map, and the story is recorded in both Swedish and Finnish accounts of the place.