Aust-Agder [ˈæʉst ˈɑɡdər] (East Agder) is a county (fylke) in Norway, bordering Telemark, Rogaland, and Vest-Agder. In 2002, there were 102,945 inhabitants, which is 2.2% of the total population in Norway. Its area is 9,212 square kilometres (3,557 sq mi). The administrative center of the county is in Arendal. The county includes the islands of Tromøy, Justøya, and Sandøya. The interior of the county encompasses the traditional district of Setesdal, through which the Otra river flows to the coast.