Leitin, meaning “the hills”, is a comparatively small shield volcano tucked away on Iceland’s Reykjanes peninsula, roughly 25 kilometres south of Reykjavík. At first glance, this volcano may appear modest, especially when compared to the towering mountains and more dramatic volcanic systems further east. Yet the lavas from Leitin and its neighbouring vents have quietly influenced the landscape, built new ground, and touched upon crucial moments in Icelandic history.
A landscape shaped by fire and time
Leitin formed about 5000 years ago during a prolonged, mostly non-explosive eruption. Its outpourings produced a vast shield of lava, known locally as Leitahraun, which flowed in broad streams both north towards today’s Reykjavík and south toward the coast near the fishing village of Þorlákshöfn. These thick, ropy pāhoehoe flows, typical for shield volcanoes, are still visible in many places, often beneath newer layers from later eruptions.
As Leitahraun advanced north, it followed the valley of the Elliðaár river, giving rise to a distinct lava field known as Elliðahraun. This flow did not simply stop at the water’s edge; instead, it triggered powerful steam explosions as the hot lava encountered swampy ground and a shallow lake, producing the cluster of rootless cones called Rauðhólar that stand at the southern edge of Reykjavík. These pseudocraters dot a 1.2 square kilometre area and are the product of violent interactions between lava and groundwater.
Leitin’s lavas also contributed to other geological formations: moving south over the pass of Þrengsli, they reached the sea in the bay of Selvogur. The flows left notable multi-coloured lava tubes, including Raufarhólshellir and Búri, which can still be explored. Outcrops of Leitin’s ancient flows are often visible beneath more recent layers, such as those produced by the nearby small craters called Nyrðri and Syðri Eldborg, which erupted around the year 1000, coinciding with major historical events.
Legend, lava, and layers of history
Different layers of lava across the region record multiple eruptions from the Brennisteinsfjöll volcanic system over millennia. The area called Svínahraun, for instance, is composed of no less than three distinct lava beds: the oldest from Leitin, a middle layer about 2000 years old, and the uppermost Kristnitökuhraun (literally “Christianisation-Lava”), which erupted during the pivotal summer when Iceland’s national assembly debated conversion to Christianity. Medieval accounts claim that, just as the decision was being weighed at Þingvellir, news arrived of an eruption nearby, some saw it as the wrath of the old gods.
The story of Leitin is not just geological; it is woven into Iceland’s nature, history, and folklore. Even modern infrastructure bears the traces of this ancient activity, as the main ring road (Hringvegur) traces a path atop some of these prehistoric lava fields. What began as an eruption five millennia ago continues to shape not only the land but also the collective memory of the communities living atop it.
Sources
- Wikipedia
- Wikipedia (Icelandic) in Icelandic
