Hrafntinnusker is a mountain in the Highlands of Iceland, located eleven kilometers and a few hours' walk from Landmannalaugar. Hrafntinnusker is also part of the famous Laugavegur hiking trail, and the Hrafntinnusker hut is the first stop for most hikers.

Hrafntinnusker is a unique place, even within the diverse landscape of the Torfajökull caldera in Iceland. It is a mountain with a tiny glacier on its summit that is rapidly disappearing. The environment is harsh, rocky, and very isolated. To the west of the mountain stretches a relatively large active geothermal area. Much of the geothermal activity also occurs beneath the ice, where the ground constantly emits hot steam that melts the ice from below and forms ice caves.