Kerið Crater
Klausturholar
General Introduction: Iceland’s Fiery Eye of the South
Kerið Crater stands as one of the most visually arresting landmarks in South Iceland, often referred to as the "Eye of the World." Unlike the dark, moody basalt found elsewhere on the island, Kerið is famous for its vibrant red slopes. This iron-rich volcanic rock creates a stark, beautiful contrast against the emerald moss and the brilliant blue water that rests at the bottom of the basin.
The crater is part of Iceland’s Western Volcanic Zone and is approximately 3,000 years old. While most of Iceland's volcanic features are ancient and weathered, Kerið remains remarkably well-preserved. Its oval shape and steep walls make it look like a perfectly carved Roman amphitheater, drawing thousands of photographers and nature lovers every year who seek to capture its unique geometry.
Located conveniently along the Golden Circle route, along with Þingvellir (Thingvellir) National Park, Strokkur Geyser, and Gullfoss (Golden Falls), Kerið is an easy addition to any day trip from Reykjavik or Keflavik. It offers a more intimate experience than the massive geysers or roaring waterfalls nearby. Visitors can spend time slowly circumnavigating the rim or taking the stairs down to the water, feeling the quiet stillness that permeates the crater’s interior.
What makes Kerið truly special is how it changes with the seasons. In the summer, the reds and greens are electric under the midnight sun. In the winter, the lake freezes into a glass-like mirror, and the red rocks are dusted with white snow, creating a minimalist masterpiece of nature. It is a site that demands a slow pace and a keen eye for detail.
The History and Formation of a Volcanic Masterpiece
Kerið was long thought to be a "maar," a crater formed by a massive volcanic explosion. However, modern geological studies suggest a different origin story. It is now believed that Kerið was once a cone-shaped volcano that erupted and exhausted its magma reserve. Once the magma was gone, the weight of the cone caused it to collapse into the empty chamber below, creating the caldera we see today.
The red color of the rocks is a result of the iron in the lava being oxidized by the air during the cooling process. This specific chemistry is what separates Kerið from the older, blacker craters in the surrounding Grímsnes area. At only 3,000 years old, it is considered a "young" crater, which explains why the colors remain so vivid and the edges so sharp.
The lake at the bottom is not formed by rainfall, but rather by the rise and fall of the local groundwater table. This means the water level inside the crater is actually the same as the water table in the surrounding earth. The minerals from the rocks and the depth of the water interact with the sunlight to create that signature opaque, turquoise hue that looks almost artificial.
Culturally, Kerið has also played a role as a unique venue for the arts. Because of its incredible acoustics, the crater has hosted several concerts. Musicians perform on a floating platform in the middle of the lake, while the audience sits on the sloping red walls of the crater. This blend of geological history and cultural utility makes it a standout site in Icelandic heritage.
3 Interesting Points About Kerið Crater
A Natural Acoustic Wonder
The shape of Kerið Crater is almost perfectly designed for sound. The steep, sloping walls act as a natural soundboard, reflecting audio from the bottom of the crater up to the rim with startling clarity. This acoustic phenomenon led to the "Lake Concerts" where spectators would line the crater walls to hear music echoing off the water.
This unique feature makes it a favorite spot for travelers to test their own voices. Even a whisper at the water’s edge can often be heard by someone standing on the opposite rim. It adds a layer of auditory magic to the visual spectacle, reminding visitors that the crater is not just a hole in the ground, but a structural marvel of nature.
The Groundwater Mirror
One of the most fascinating aspects of the Kerið lake is that it is a direct window into the earth’s water table. Because the lake isn't filled by rain or a stream, the water level remains consistent with the surrounding landscape's moisture levels. This makes the lake a living barometer of the Icelandic environment.
The water itself is incredibly deep and clear, though the minerals give it an opaque quality. Depending on the time of day and the cloud cover, the lake can shift from a deep navy blue to a bright, milky neon green. This "mirror" effect at the bottom of the red cauldron creates some of the most famous reflection photos in all of Iceland.
A Rare Private Landmark
While most of Iceland’s natural wonders are state-owned, Kerið is unique because it is situated on private land. The owners maintain the site with great care, using a small entrance fee to build the safe walking paths and the wooden staircase that leads to the lake. This private stewardship has allowed for better preservation of the fragile moss and volcanic soil.
Being a private site has also allowed for unique conservation efforts. The paths are designed to prevent the erosion of the red scoria (volcanic rock), ensuring that the crater remains as pristine for future generations as it was 3,000 years ago. It stands as a successful model of how tourism and private land ownership can work together to protect natural beauty.