The name "Thórsmörk" properly refers only to the mountain ridge between the rivers Krossá, Þröngá, and Markarfljót,[1] but is sometimes used informally to describe a wider area that includes the region between Thórsmörk and Eyjafjallajökull.

In the protected valley, green vegetation of moss, fern, birchwood, and other small shrubs are found.

Many 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.

During the spring 2010 eruptions of Eyjafjallajökull, much of the area was covered in a thick layer of volcanic ash.