Leirhnjukur is a volcanic mountain and geothermal area within the Krafla volcanic system north of Lake Myvatn. It is especially known for features created during the 1975–1984 Krafla Fires, including young lava, fissures and colourful geothermal ground. Walking routes around Leirhnjukur provide an excellent view of how volcanism and geothermal activity shape Iceland's active rift zone. Hot ground and steam can occur close to the surface, so visitors should follow marked trails and take care around fragile formations.