Gjáin (Icelandic pronunciation:[ˈcauːɪn]ⓘ) is a small valley with small waterfalls, ponds, and volcanic structures situated in Þjórsárdalur in the south of Iceland.[1] It is to be found at about half an hour walking distance from the historical farm Þjóðveldisbærinn Stöng. Through the valley runs the river Rauðá with the waterfall Gjárfoss.