Hverfjall (also called Hverfell) is a popular tephra cone within close proximity to Lake Myvatn. This extinct volcano hasn’t erupted for roughly 4,500 years and now serves as a popular hiking area. The diameter of this crater is only 1 kilometer, and the 3-kilometer hike around the top takes roughly an hour.
Though the hike around the top has little elevation change, the hike up is a steady ascent. It may take 10 minutes at a nice clip, but the slower hiker would be wise to take their time and bring plenty of water, budgeting around 20 minutes to the plateau. Good hiking shoes are recommended, as loose rock is abundant, and footing is not especially stable. It is forbidden to ascend or descend the rim on any path other than the one obviously provided—except for one other path from Dimmuborgir, which is not detailed here.