Aust-Agder (oustˌ-ägˈdər) [key], county (1995 pop. 99,585), 3,610 sq mi (9,350 sq km), S Norway, bordering on the Skagerrak in the east. Arendal is the capital. The Setesdal comprises the county's northern section. The Otra is the main river. Major industries include forestry, shipping, agriculture, tourism, and mining (nickel and iron). The county was formerly called Nedenes.