Østermark is a settlement in Samsø Municipality, in the region of Central Denmark, Denmark. Østermark lies at 6 m above sea level. The nearest city is Aarhus, 31 km to the northwest. Among the landmarks around are Stenstuen (8.8 km), Nils Halses Høj (8.8 km) and Tunø Church (7.7 km). Among the natural features are Ballebjerg (2.8 km).