Austmarka is a village in Alver Municipality (formerly Radøy Municipality) in Vestland 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. The 0.23-square-kilometre (57-acre) village has a population (2019) of 371 and a population density of 1,613 inhabitants per square kilometre (4,180/sq mi).