In Dimmuborgir [ ˌ dɪ.mʏ bɔ ɹ.giɹ ː ] ( Isl dark cities or dark castles ) is a lava field and the remains of a lava lake east of Lake Mývatn in Iceland. It is located in a volcanically active region in the field of the volcano Krafla system, directly east of the lake. To the northeast lies adjacent to the tuff ring Hverfjall.

The bizarre rock formations of the lava field are reminiscent of crumbling ruins of castles and towers. In Icelandic mythology Dimmuborgir is seen as an inn of elves and trolls.