|Location||Froland and Åmli|
|Max. length||8 kilometres (5.0 mi)|
|Max. width||3 kilometres (1.9 mi)|
|Surface area||10 km2 (3.9 sq mi)|
|Shore length1||68 kilometres (42 mi)|
|Surface elevation||138 metres (453 ft)|
|1 Shore length is not a well-defined measure.|
Nelaug is a lake in the municipalities of Froland and Åmli in Aust-Agder county, Norway. The 10 kilometres (6.2 mi) lake is formed by a dam which regulates a hydroelectric power plant on the Nidelva river. The village of Nelaug is located near the dam in Froland municipality. The lake is located about 11 kilometres (6.8 mi) south of the village of Åmli, about 15 kilometres (9.3 mi) southeast of the village of Dølemo, and about 20 kilometres (12 mi) north of Blakstad.