Kungsberget Nature Reserve covers 79 hectares, six kilometres north-west of Järbo. Its habitats include old conifer forest, deciduous woodland that floods at times, steep rock faces and areas of loose boulders. Several marked trails cross the reserve, and visitors can walk or, on some trails, cycle. Cycling off the trails is not allowed.

Styggbergsbranten is a south-facing slope with plants including hazel, touch-me-not and golden shaggy-moss. The slope holds old mixed conifer forest, dead wood and mature deciduous trees, especially aspens. Below it, boulders form a network of caves. The longest cave is 25 metres long and is called Gillbergs ide, after a robber who, according to local legend, used it as a hideout. Visitors can grill and rest at Gillbergs ide.

Lillån forms the reserve’s northern boundary and runs through deciduous woodland that floods periodically. A barn remains from the time when parts of the area were open grazing land. Other traces of past activity include charcoal-burning platforms, remains of forest huts and a ski-jumping hill from the 1930s. The reserve’s website warns that storm-felled trees have affected the area and says trees that blocked trails and paths have been cut and moved aside; it advises visitors to take care.