The area is located in a hilly peninsula between Tunaviken and Sätterfjärden northwest of Trälhavet.
Due to the height differences and the possibility to get a sea view speed up the building process.
Among other things in Österskär, there was a smaller feldspar and quartz mine as well as a mansion (Tuna Gård).
During the 1900s, plans to make Österskär an exclusive suburb was settled, and several large villas were built along the coastline.
Österskär has relatively high real estate prices compared to rest of Sweden and is one of northern Stockholm's most exclusive suburbs.