Þórsmörk is a valley in Iceland that was named after the Germanic god Thor (Þór). It is situated in the south of Iceland between the glaciers Tindfjallajökull and Eyjafjallajökull. Here, the river Krossá winds between the mountains. In the protected valley, there is green vegetation including moss, fern and birchwood. The Krossá is a very cold river coming down from the glaciers. It is dangerous to cross the river, but a bridge has been installed for pedestrians.

The valley is closed in between glaciers, Mýrdalsjökull being at the rear end of the valley. This leads to an especially warm climate, better than in the rest of south Iceland. Þórsmörk is also very popular with hikers. A lot of different tours are possible, from hiking on the glaciers to trekking (i.e., Laugarvegur up to Landmannalaugar) or smaller excursions, such as to the canyon Stakkholtsgjá with its waterfall. Reykjavik Excursions operates scheduled bus tours to and from Thorsmork and accommodation in Husadalur Valley.