The small valley Gjáin with its small waterfalls, ponds, and volcanic structures is situated in the south of Iceland. It is to be found at about half an hour walking distance from the historical farm Þjóðveldisbærinn Stöng.
The volcano Hekla can be seen from the site.
Source: https://en.wikipedia.org/wiki/Gj%C3%A1in
Gjáin er hluti af Þjórsárdal.