The sandstone outcrop Hellnaskagi is on the property of the southernmost farm of the country, Gardar. It stretches westwards into the Dyrholar Lagoon and on its top are the ruins of farm Hellar, which was abandoned in 1909. Other manmade caves, Graenkelluhellir, Hrossatrod and Heyhellir (now collapsed), are there as well. Cave Badstofuhellir is best known for Reverend Jon Steingrimsson’s stay there for a part of the winter of 1755. At that time, the cave probably was connected to the farm houses as a tunnel on the right hand side of its entrance suggests. Jon chiselled a larger space for himself, and lived in the cave with his brother for a while. During the stay, Jon studied the German language and got interested in the history of volcanism. When the brothers were preparing their stay in the cave, a major eruption started in the Katla Area. District Magistrate Jon Sigurdsson wrote a report on it.
Jon Steingrimsson based his personal and much more detailed report on it. Later in his life, after having served as a Reverend in the Sida Area for years, he wrote a renowned report about the Skafta Eruption (Sida Fires; 1783-84), which is a priceless source for scientists.
Cave Badstofuhellir is about 6 metres long, almost 3 metres wide, and 2 metres high. The arch shaped nieche in the end wall probably is the work of Jon Steingrimsson. The walling in the entrance its woodwork with doors and windows made the cave a comfortabel abode. The last time the cave was used, some sheep were kept there.
Source: The Memoirs of Eyjolfur Gudmundsson (Memoirs from Myrdalur pg 64).
Badstofuhellir Cave is on the Saga trail for South Iceland.