Lake Eidisvatn has an area of 1,9 km². Its greatest depth is 3 m and it is situated 1 m above sea level.
The three brooks, Thrilaekir, feed it and it is discharged into the cove Eidisvik. A passable road lies to the lake and there is an airstrip at Saudanes. The lake abounds in excellent sea char. A few years ago an experiment with salmon rearing in the lake with bearable results was carried out. The lake is netted.
The distance from the capital is 689 km by the Whale Bay tunnel and 18 km from Thorshofn.