Salskären lies in the centre of Svartlögafjärden, between Blidö and Svartlöga. The reserve comprises the north-eastern part of Salskären, with Tistronörarna and Norrören.
The vegetation of Salskären consists of a large, flat area of juniper bushes. There are occasional open patches with vegetation that is typical for such patches. The centre of Salskären is alder forest, while the stands on northern Salskären are mixed, with spruce, birch and alder. The vegetation on the smaller islands is similar. The beaches are flat, and consist of mixed plane rocks and stones. The islands have a rich birdlife.