Mt Lomagnupur is a prominent 688 m high and precipitous promontory on the south coast.  It is the southernmost end of Mt Bjorninn just west of River Nupsvotn of the Skeidararsandur alluvial plain.  A few obvious remains of great landslides dot the landscape, one from 1790 near the ring road close to the mountain, and another more recent (1998) in the eastern slopes.  Like other promontories of the south coast, Mt Lomagnupur was a headland during the Ice Age.

Mt Lomagnupur is mentioned in the Njal's Saga in connection with Flosi of farm Svinafell’s dream, when he saw the giant of Lomagnupur step out of the mountain.  This giant holding his iron pole is one of the four protecting ghosts of the country depicted in its code of arms.  He is the protector of the south coast.