The mountain rises about 100 metres above the surrounding landscape, with steep dolerite slopes to the north and a less steep approach to the south. Ålleberg is situated on Falbygden’s limestone plateau and the mountain itself consists of clay shale and dolerite. Dolerite is only found in the northern section. The limestone extends around the mountain and provides fertile and nutrient-rich agricultural soil. The geology here favours particular types of plants, with broadleaf trees on the mountain slopes and species-rich meadowland and pasture.
Ålleberg has been a popular site for gliding since 1941, and there is still a gliding school and a gliding museum here today.