Lake Eidavatn has an area of 1,7 km² and is situated 32 m above sea level. River Eidalaekur empties into it and its discharge, Fiskilaekur, tributes to the glacial river Lagarfljot.
The catch consists mainly of lake char and a few brown trout are caught as well. The lake is netted every now and then. There is a tiny wooded islet on the lake and quite a few holiday houses have been built around it.
The distance from the capital is 712 km and 14 km from Egilsstadir.