This lava cave is within easy reach just east of the main road leading to the ferry town Thorlakshofn, where the road starts descending in the South. It is about 1360 metres long, 10-30 metres wide and up to 10 metres high. The average thickness of the ceiling is about 12 metres, except where the road crosses it. There it constantly grows thinner because of the traffic.

It is highly recommended to walk all the way to its utmost end to see the beautiful lava formations there, but the trip is very arduous because of the great number of heaps of boulders, which have to be conquered en route and the constant ice formations on the floor. The existence of the cave has been known for a long time and too many people have left all kinds of garbage down there and removed the stalactites and lava ropes.

About halfway through the cave was a framed document, an epitaph, and a cinerary urn on a lava ledge. The urn contained the earthly remains of the last member of an Indian tribe from the Fire Island. It was brought there by a German friend of this Indian and later removed by someone. The lava field, in which the cave is situated, is said to have been created during a fissure eruption in the year 1000, leaving an 11 km long crater row.