Thórsmörk (Icelandic: Þórsmörk) is a mountain ridge in Iceland that was named after the Norse god Thor (Þór). It is situated in the south of Iceland between the glaciers Tindfjallajökull and Eyjafjallajökull. The name "Thórsmörk" properly refers only to the mountain ridge between the rivers Krossá , Þröngá and Markarfljót, but is sometimes used informally to describe a wider area that includes the region between Thórsmörk and Eyjafjallajökull.
In the valley, the river Krossá winds between the mountains. 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. In the protected valley, there is green vegetation of moss, fern, birchwood and other small shrubs.
Thórsmörk is popular amongst hikers. A lot of different tours are possible, from hiking on the glaciers to trekking (i.e., Laugavegur up to Landmannalaugar) or smaller excursions, such as to the canyon Stakkholtsgjá with its waterfall or five small day treks, to the summits of surrounding peaks, with rewarding views, even in bad weather. The Krossá is a cold fast river coming down from glaciers: a bridge allows pedestrians to cross. There are daily coach arrivals, from Reykjavík and other towns in Iceland.