Austmarka is a village in Radøy municipality in Hordaland county, Norway. The village is located on the southern end of the island of Radøy, about 2 kilometres (1.2 mi) east of the village of Sæbø and about 5 kilometres (3.1 mi) north of the village of Alverstraumen (in Lindås municipality). The 0.22-square-kilometre (54-acre) village has a population (2013) of 385, giving the village a population density of 1,750 inhabitants per square kilometre (4,500/sq mi).