The mountain rises about a hundred metres above the surrounding landscape, with steep dolerite slopes to the north and a less steep approach to the south. The types of rock we find on Ålleberg are the same as on all the table mountains (sandstone, alum shale, limestone, clay shale and dolerite).Dolerite is only found in the northern section, and there are breathtaking views from its peak. The limestone extends around the mountain and provides together with the alum shale fertile and nutrient-rich agricultural soil. The geology here favours particular types of plants, with broadleaf trees on the mountain slopes and diverse meadowland and grazing land.
Ålleberg has been a popular site for gliding since 1941, and there are still a gliding school and gliding museum here today.