Österskär

59°27′42″N 18°18′40″E / 59.46156°N 18.31100°E / 59.46156; 18.31100

Österskär is the eastern part of Åkersberga, Österåker Municipality in Sweden. It hosts the terminal station of the Stockholm suburban railway Roslagsbanan.
The area is located in a hilly peninsula between Tunaviken and Sätterfjärden northwest of Trälhavet. Many Stockholmers have their boats in one of Österskär's many marinas. There is a residents association.