Melrakkaslétta is a lowland area in northeast Iceland, located on a peninsula between two wide open fjords, Öxarfjörður in the west and Þistilfjörður in the east. The area is on the eastern edge of the northern volcanic zone of Iceland. Two Holocene fissure swarms, originating from active central volcanoes in the interior of Iceland, extend north to the peninsula. One of them ends in the cape Rauðinúpur, an old volcano on the northwest coast of the peninsula. The other ends in the valley of Blikalónsdalur which is actually a rift valley, extending from the north coast and further 20 km inland.
The greater part of Melrakkaslétta is built of grey basalt from the Pleistocene period but young tuff (palagonite) is characteristic of the westernmost part of the peninsula, especially north from the village of Kópasker. Water penetrates easily through the young bedrock that is characteristic of the western part, so there is not much surface water in that area. Instead the water flows as groundwater and emerges as spring water close the shore or where faults and fissures cross the surface. The older bedrock in the north eastern part is less permeable, creating numerous freshwater lakes, ponds and rivers that extend from the coast and further inland, especially in the area close to Raufarhöfn.