The mountain Hafnarfjall near Borgarnes is part of the same extinguished central volcano as Skardsheidi and also about 4 million years old.
The mountain is 844 m in height and its sides are rather eroded. Most of the mountain consists of basalt, but on the north side there is a small crag, which is made of granofyr. The name "flatfish" indicates its form. Let the children discover it!
On the foot of the mountain is a small forest of birch trees where the authorities of Iceland practice reforestation. It is possible to hike up the mountain beginning near the bridge over the fjord at Borgarnes.