Gunnuhver geothermal area
Gunnuhver is Iceland's largest boiling mud pool, a highly active geothermal field on the southwestern tip of the Reykjanes Peninsula within the Reykjanes UNESCO Global Geopark. Steam vents, bubbling mud pots, and fumaroles cover the landscape, with mineral deposits turning the surrounding rock vivid shades of yellow, orange, and red. It is one of the most dramatic and accessible geothermal areas in the country, just 20 minutes from Keflavik International Airport.
Iceland's Largest Boiling Mud Pool and the Ghost That Gave It Its Name
Gunnuhver sits on the Reykjanes Peninsula where the Mid-Atlantic Ridge rises above sea level, making this one of the most volcanically active patches of land on earth. The area's groundwater is 100% seawater, drawn in from the nearby ocean and superheated by volcanic activity deep underground to temperatures exceeding 300 degrees Celsius before it forces its way back to the surface. The result is a constantly active field of fumaroles, hot springs, and the 20-metre wide central mud pool, the largest boiling mud pool in Iceland, which churns and bubbles with escaping gases and scalding water. The mineral-rich steam has chemically transformed the surrounding basalt rock into a vivid palette of yellow sulphur, orange iron oxide, and white silica deposits.
The name Gunnuhver comes from a local ghost story. According to Icelandic folklore, a woman named Guðrún Önundardóttir, known by her nickname Gunna, became a troubled spirit after a dispute with a wealthy neighbouring farmer went unresolved at her death. Her ghost was said to terrorise people and animals in the area until a priest finally managed to trap her and cast her into the hot spring, which has borne her name ever since. A sign at the site tells the full story. The area is part of the Reykjanes UNESCO Global Geopark, one of only a handful of geoparks worldwide sitting directly on a mid-ocean ridge above sea level.
A boardwalk with two viewing platforms leads visitors safely through the geothermal field. Entry is free and the site is accessible year-round, though boardwalks can be icy in winter. Gunnuhver is located off Road 425 near the Reykjanesviti lighthouse on the southwestern tip of the Reykjanes Peninsula, about 20 minutes from Keflavik International Airport and around 50 kilometres from Reykjavik. It pairs naturally with the Bridge Between the Continents, the Reykjanes lighthouse, and the Blue Lagoon as part of a Reykjanes Peninsula day trip.
