This name refers to the largest lava area of the country (5600 km²). Its boundaries are: The Vatnajökull glacier in the south, river Skjalfandafljot in the west, river Jokulsa in the east and in the north they are rather vague. The northern elevation of the area is about 400 m above sea level but in the south about 800 m. Quite a few freestanding mountains and a massif rise above this plateau, such as Herdubreid (1682m) and Dyngjufjoll (Askja). The lava fields are relatively easy to travel if people show foresight and carry water supplies with them, when hiking through the area. The only problem is the lack of water in the permeable lava fields.
This part of the country had not yet been explored, when the Englishman William Lord Watts was crossing the icecap Vatnajökull in 1875. When he and his Icelandic companions arrived at the northern edge of the glacier, they witnessed the enormous eruption of Askja and reported it to the people at lake Myvatn. A few tales and one of the sagas, Hrafnkel’s Saga, mention a route through the area in connection with the so-called Sprengisandur route. People have been searching for the old route through Odadahraun and it has most likely been found.