Lónsöræfi () is a wilderness area in south-east Iceland. The region is characterised by its varied geological formations. These mostly date from a period between 5 and 7 million years ago, when the volcano Kollumúlaeldstöðvar was active. The glacier tongues of the eastern extreme of Vatnajökull also impose themselves on the area. Visible to the north-west is Snæfell (1833m), the highest peak in Iceland that isn't part of a glacier. The mountains within the area itself include Sauðhamarstindur (1319m) and Jökulgilstindar (1313 m).
