The Lilla Husarn nature reserve includes the main island together with Husarholmen, Simpskallen, Stora Saltkråkan, Lilla Saltkråkan, Stora Kråkskären and Lilla Kråkskären.
The area has a number of good natural anchorages. The islands hold a strategic position between Jungfrufjärden and Nämdöfjärden, and are consequently visited by many people. Sea routes from the north over Nämdöfjärden and those from the northwest over Ingaröfjärden all meet here.
The area, with the exception of Stora and Lilla Kråkskären, became a nature reserve in 1981, and was then state-owned. The Archipelago Foundation acquired the island group in 1992, when Stora and Lilla Kråkskären were also included in the reserve.