Hallmundarhraun, a lava field from craters at the northwestern edge of the Langjökull glacier, reaching north of the Eiríksjökull glacier along the Norðlingafljót river valley to the river Hvítá near Gilsbakki.
Parts of it are known as Skógarhraun and Gráhraun. Not difficult to cross in most places.
Big caves Kalmanshellir, the biggest known cave in Iceland, Víðgelmir, Surtshellir and Stefánshellir, and other smaller ones.