Your route starts at the hiking car park at the Stern. Initially, you first go 700 m flat to a wood collection area, from where there is then just under 500 m of slightly downhill stretch. At a junction, you have to turn almost at a right angle to the left. Passing some rocks, you reach the first small ascent before it becomes flat again immediately afterwards. Now you have reached the farthest point of the Jonsberg loop.
The return route runs on the Jonsdorf side of the Jonsberg. Here comes another ascent in the form of an S. The good news: this is the second to last time it goes uphill. At a fork, you take the steep path and keep to the left. Then it goes through a beech forest. Now you have made it, as it only goes slightly downhill, with some small, fast sections in between. After a right turn, you can already see the car park.