Hallmundarhraun Lava Field

Hallmundarhraun flowed from an eruption of one of the volcanoes lying under the Langjokull glacier around the year 930. Consisting of dark basaltic rocks covered in soft moss, there are wonderful formations, frozen ripples, crevasses, and Surtshellir cave located underneath. The ancient lava flow is named after a cave-dwelling giant from the Saga of Grettir the Strong.

Hallmundarhraun is a lavafield that formed shortly after Iceland's settlement, in the 10th century. It is named after Hallmundur which according to Gertis Saga lived in this area. The craters from which the lava flowed are located below Langjökull. The eruption is likely to have been protracted and lasted for several years. It is over 200 km² in area. The largest part of the lava is 7 km and its total length is 52 km.

A remarkable narrative of this eruption is in an ancient song called Hallmundarkvida or Poem of Hallmundur. This is the oldest description of an eruption in Iceland. There are reports of earthquakes, ash, lava flow and deaths caused by the eruption. It is likely that the eruption has occurred around 940. There may be some farmsteads that went under the lava.

In Hallmundarhraun there are many caves, the most famous are Víðgelmir, Stefánshellir and Surtshellir.