The waterfall Háifoss is situated near the volcano Hekla in southern Iceland. The river Fossá, a tributary of Þjórsá, drops here from a height of 122 m. This is the fourth highest waterfall of the island, after Morsárfoss, Glymur and Hengifoss.
Granni is Icelandic for neighbor and it is the name of the waterfall to the right, being the neighbor of Háifoss.
From the historical farm Þjóðveldisbærinn Stöng, which was destroyed by a volcanic eruption of Hekla in the Middle Ages and reconstructed, it is possible to hike to the waterfall along the Fossá (5 to 6 hours both directions). Above the waterfall, there is also a parking lot, to allow hiking to be done in the other direction.