Once separated from the mainland by a natural sound, this navigable route was rendered unusable in more modern times by post-glacial rebound and has been replaced by the artificial Draget Canal.

Unusually for Stockholm County, the island has several sandy beaches which are a habitat for a number of red listed plants.

The islands surrounding Järflotta, especially Gunnarshögarna, are also included in the nature reserve and support important habitats for birds such as Caspian tern, razorbill, black guillemot and common murre.

The explicit purpose of the nature reserve is to preserve an important archipelago environment and make it accessible for recreation and, for the outlying islands, to protect the bird-life.

The coastal artillery battery, which dates from 1942, is part of a series of fortifications built during World War II to protect Södertälje and Nynäshamn from attack and minefields in the Baltic Sea.