The abandoned farm Theistareykir, and the surrounding area with the same name, is accessible by a road from the county Kelduhverfi and Husavik by the moorland Reykjaheidi. This road continues all the way south to the Holssandur road, which connects The Lake Myvatn area with the town Husavik. The immediate surroundings of the ruins of the farm are well vegetated and green in spite of their 344 m elevation. In the past, the nearest church, Grenjadarstadur, was about 19 km away.

The farm was finally abandoned in 1874, but now a nice shelter of the farmers for the period of the round up of the sheep stands there. Theistareykir and the shield volcano Theistareykjabunga are one of the high temperature areas feasible for exploitation in the near future. In the past sulphur was mined there and processed before it was shipped to Copenhagen.

According to the legend, 12 polar bears once visited the farm and killed the people. The farmer’s son, who had been absent at the time, came back home only to find a few parts of his mother’s body. He chased the animals and killed them all. There is also some talk about a ghost, a brown, and monster like dog, which haunted the farm. The shield volcano rises only 564 m above mean sea level and has a very gradual slopes. Its crater is about 550 m long, 50-60 m wide and 40 m deep. Two other craters, Stora- and Litla Viti are south of the shield volcano. Great lava fields in the Kelduhverfi County originate from them.

During the summer of 2002, a few experimental boreholes were sunk in the area to test the capacity of the high temperature area for future exploitation.