A highland hike through an exceptionally colourful rhyolite mountain range with active geothermal areas, crossing orange and red volcanic ridges streaked with fumaroles and steaming vents. The Hveradalir geothermal valley at the heart of the range is one of Iceland's most visually striking highland landscapes.
The trailhead sits at Ásgarður Mountain Lodge in the Kerlingarfjöll highlands, reached via the F347 road from Route 35, passable to high-clearance 4WD vehicles roughly from late June to September; a summer highland bus also serves the lodge. The 12 km loop gains around 600m, following marked paths across rhyolite ridges and volcanic ash slopes with sections of loose scree underfoot; boardwalks protect the ground through the most fragile geothermal areas. The route's centrepiece is the Hveradalir geothermal valley, a basin of steaming fumaroles, boiling mud pots, and mineral-streaked slopes in vivid orange, red, and yellow, crossed on raised boardwalks to protect the sensitive ground and keep hikers clear of scalding vents. Beyond Hveradalir, the loop climbs onto higher ridgelines for 360-degree views over the central highlands, with exposure to wind and rapid weather changes at altitude and no shade anywhere on the route. There is no shelter along the loop itself; Ásgarður Mountain Lodge at the trailhead is the only base with huts, camping, food service, and reliable water, and hikers should return there before dark given the remote, exposed setting. Given the geothermal terrain, hikers should stay on marked paths and boardwalks at all times, as ground near fumaroles can be unstable and scalding.
| Distance | 12 km loop |
|---|---|
| Duration | 5-7 hours |
| Difficulty | challenging |
| Trailhead | 4WD required |
| Best season | July-August |
| Address | Ásgarður Mountain Lodge, Kerlingarfjöll, Central Highlands |
Trail facts
- Trail area
- Kerlingarfjöll, Central Highlands
What to bring
- hiking boots
- waterproof jacket
- trekking poles
- sun protection
- warm layers
Weather through the year in Iceland
Best time Shoulder Worth avoiding
Average daytime temperature in °C. Figures are for Iceland.
Location
Ásgarður Mountain Lodge, Kerlingarfjöll, Central Highlands
64.6320, -19.0000 View on map
Highlights
- Hveradalir geothermal valley
- Vivid rhyolite colour palette
- Steaming fumaroles and hot springs
- 360-degree highland panoramas
Tips for visiting
- Stay on the marked boardwalks through the Hveradalir geothermal area; the ground near fumaroles can be unstable and dangerously hot.
- The F347 access road requires a high-clearance 4WD and is only open roughly late June to September.
- Pack for sun exposure and sudden wind on the exposed ridge sections, as there is no shade anywhere on the loop.
- Ásgarður Mountain Lodge offers the only huts and food service in the area; book ahead for peak summer dates.
- Trekking poles help with the loose scree on the ridge climbs.
When to visit
Mid-July through August offers the most reliable F-road access and the clearest views over the geothermal valley and surrounding ridges.
Accessibility
The loop crosses loose scree, volcanic ash, and boardwalks over geothermal ground, so it is not accessible to wheelchairs or strollers.
Frequently asked questions
What makes Kerlingarfjöll's colours so vivid?
The rhyolite rock combines with active geothermal activity to produce a striking range of orange, red, and yellow mineral staining, especially concentrated in the Hveradalir valley at the centre of the loop.
Is it safe to walk off the marked paths near the geothermal area?
No, the ground around the fumaroles and hot springs in Hveradalir can be thin and scalding beneath the surface, so hikers should remain on the boardwalks and marked trail at all times.
How do hikers reach Kerlingarfjöll?
The F347 road from Route 35 requires a high-clearance 4WD vehicle and is typically only open from late June to September; a seasonal highland bus also connects to the lodge.
Is accommodation available near the trailhead?
Ásgarður Mountain Lodge at the trailhead offers huts, camping, and a restaurant, making it a practical base for the day loop or for staying overnight in the highlands.