Some of Hengill’s best scenery can be enjoyed on a hike through Reykjadalur, nicknamed “Smoky Valley” for the steam emanating from several thermal springs in the area. From Hvergerði, a gravel trail leads hikers into the valley, and as the trail gradually ascends, the thermal waters become warmer.
The reward for the relatively easy hike is a chance to soak in a thermal river. The point where the thermal water merges with a cold river is one of the best spots, but hikers can head up or downhill to find their perfect temperature. The area has numerous signposted hiking trails, including an hour-long trail that circumnavigates Öklelduhnúkur and another that continues all the way to Þingvallavatn.
The trail begins just 40 minutes outside Reykjavik in the town of Hvergerði.