Temperature
300°C+ underground
Surface temperatures at vents exceed 100°C; subsurface far hotter
Gunnuhver: Powerful Mud Pools & Steam on Iceland's Reykjanes Peninsula
Iceland's largest mud pool and one of Europe's most powerful geothermal vents, named after a ghost from Icelandic folklore.
Location
Reykjanes tip
Reykjanes Peninsula • Near Reykjanestá
Quick Answer
Gunnuhver on the Reykjanes peninsula is Iceland's largest mud pool, named after a ghost from folklore. Boardwalks pass boiling mud and steam vents; stay on them.
Gunnuhver is a geothermal area near the southwestern tip of the Reykjanes peninsula, just minutes from the Reykjanestá lighthouse. It is home to Iceland's largest mud pool, a roiling cauldron of gray, boiling mud, and to some of the most powerful steam vents in Europe, which send columns of steam high into the air. The area is named after Guðrún Önundardóttir (nicknamed Gunna), a ghost from local folklore who was reportedly trapped in the hot spring by a priest in the local legend. A boardwalk system lets visitors view the mud pools and fumaroles from a safe distance. The area sits atop the Mid-Atlantic Ridge where the North American and Eurasian tectonic plates meet, and has become more active in recent years alongside the broader Reykjanes volcanic unrest.
Sources and page update
Updated: 2026-09-10
Extremely high temperatures. Stay on boardwalks at all times; the ground can collapse without warning. Check volcanic alerts for the Reykjanes area before visiting.
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Official sources to check
Entrance Fee
Free
Boardwalk access year-round, parking at the site
Distance
~50 km
From Reykjavík, about 50 minutes via Route 41 and 425
What to Expect
Massive Mud Pool (100°C+)
Iceland's largest mud pool: a churning cauldron of thick, boiling gray mud several meters across, with surface temperatures exceeding 100°C
Powerful Steam Vents
Enormous columns of steam rising 15-20 meters from fissures in the earth, visible from a considerable distance. Underground temperatures exceed 300°C
Safe Boardwalk System
Maintained boardwalks and viewing platforms allow close but safe observation. The boardwalk loop takes 20-40 minutes. Free admission, open year-round
Folklore of the Ghost Gunna
Named after Guðrún Önundardóttir, a 13th-century ghost reportedly trapped in the hot spring by a priest. Information signs at the site tell the full saga
What to Bring
Windproof jacket (the Reykjanes tip is extremely windy), sturdy shoes, and a camera. No swimming or bathing; this is a viewing-only geothermal site
Reykjanestá Lighthouse Nearby
Iceland's oldest lighthouse (built 1878) is a 5-minute walk from Gunnuhver, standing on coastal cliffs with views across the Atlantic
Getting There
From Reykjavík, drive south on Route 41 toward Keflavík, then continue southwest on Route 44 and Route 425 to the tip of the Reykjanes peninsula. The total drive is approximately 50 km (50 minutes). A free parking area with an information board is located at the site. The boardwalk to the viewing platforms is short, flat, and wheelchair-accessible. No 4WD required; the route is fully paved. The nearest town is Grindavík (15 km). Combine with the Reykjanestá lighthouse (5-minute walk), the Bridge Between Continents at Sandvík (10-minute drive), and Krýsuvík-Seltún (30-minute drive) for a full Reykjanes geothermal day trip.
Best Time to Visit
Year-round, with conditions varying by season. November through February: the steam columns are at their largest on cold, calm winter days, rising tall and straight against dark skies. Northern lights are sometimes visible from the area. March through May: lengthening days with moderate crowds and spring light on the coastal cliffs. June through August: longest daylight and mildest temperatures, but also peak tourist season. The Reykjanes peninsula is Iceland's windiest region, so bring windproof layers in any season. September through October: a quieter shoulder season. Always check SafeTravel for volcanic activity alerts in the Reykjanes area, as eruptions have occurred nearby since 2021.
Why a hot spring becomes a mud pool
Visit Reykjanes explains that steam condenses and mixes with surface water. Gases make that water acidic, altering fresh lava rock into clay. The bubbling mud is therefore part of an ongoing chemical change in the rock.
The regional guide identifies two viewing ramps: one by Gunnuhver and another on the silica hill Kísilhóll, looking over the wider group. Use whichever established viewpoints are open; do not leave them if wind carries steam across the view.
Planning help
Gunnuhver FAQs
Quick answers with safety notes where it matters.
Is Gunnuhver safe to visit?
Use only the open boardwalks and viewing platforms and obey closures. This is a boiling mud-and-steam area, not a bathing place. Do not step onto the surrounding ground to get around steam or take a photograph.
Who was Gunna and why is the area named after her?
Visit Reykjanes relates the story of a female ghost called Gunna whom a priest trapped in the spring. This is folklore explaining the name, not a documented account of the geothermal feature’s formation.
How long does a visit to Gunnuhver take?
A visit to Gunnuhver typically takes 20–40 minutes. The boardwalk loop is relatively short, passing the main mud pool and several steam vents. Combine it with nearby Reykjanestá lighthouse (Iceland’s oldest, just a short walk away) and the Bridge Between Continents for a half-day on the Reykjanes peninsula.
Is Gunnuhver connected to recent volcanic activity?
Surface activity has more than one influence. Visit Reykjanes links a marked increase in steaming to pressure drawdown when geothermal production began in 2006. Check current regional volcanic notices separately; a change in visible steam is not by itself a visitor’s eruption forecast.
For a countrywide view of Iceland’s volcanic systems, explore our Iceland statistics.