Three large outlet glaciers characterise the area consisting of Hjallanes (west of the river Kolgríma) and Heinaberg (east of the river). It is rare to find glaciers so close to a whole district. Large herds of reindeer can often be seen in the area, from autumn through to spring.

During the Little Ice Age and in the early 20th century the Skálafellsjökull and Heinabergsjökull glaciers were adjoining in front of Hafrafell. Hjallanes was covered by a glacier, and signs of this can be seen: glacial erratics, striations and whalebacks.

When Heinabergsjökull was at its maximum size it blocked the entrance to Vatnsdalur and Heinabergsdalur. As a result water accumulated in the valleys. Occasionally, water forced its way under the glacier and burst onto the lowland. Glacial outbursts floods from Vatnsdalur were notorious for destroying farmland.

The Heinaberg farm stood below Heinabergsfell, until it was abandoned in the 1930s. The farm is named after Heinar, distinctive rock ridges with columnar jointed basalt that are located nearby. The name Heinar is possibly derived from their similarity to the slick, smooth stones used to sharpen blades – heinar in Icelandic. Alternatively, the name may derive from heiðnar, meaning “heathen”.