Gyvatn is a lake in Agder county, Norway. The lake straddles the borders of the three municipalities of Åseral, Bygland and Evje og Hornnes. The 4.62-square-kilometre (1.78 sq mi) lake is located about 8 kilometres (5.0 mi) northwest of the village of Byglandsfjord and the lake Byglandsfjorden and it is about 7 kilometres (4.3 mi) east of the village of Åknes in Åseral.[1]