Gjallandi is the uppermost waterfall in the river Skjálfandafljót. The source of the river is in Vatnajökull, from glacial rivers that run from the pass Vonarskarð and from under Bárðarbunga, including the stream Rjúpnabrekkukvísl. The river Skjálfandafljót runs to the north between Sprengisandur and Ódáðahraun, though the valley Bárðardalur and into the bay Skjálfandi. Other waterfalls include Aldeyjarfoss, Hrafnabjargarfoss and Goðafoss. Skjálfandafljót is a clear-water, part glacial river, which means that the waterfall can variously be clear, milk-coloured or peat-brown. On the drive through the expanses to the north of the glacier Tungnafellsjökull the waterfall is just to the south of the route named Dyngjufjallaleið, and it is well worth the traveller's time to take a short detour in order to have a look at it. Gjallandi used to have a stone arch and therefore it was sometimes named Steinbogafoss ("stone arch waterfall"). The only picture that exists of the stone arch is from the summer of 1952, but it is not known for certain when the arch collapsed.