Walking Flue Crests in the Jura Hills to Ruins of Waldenburg Castle

Sunday March 9, 2025 -- This is a hike we have wanted to do for quite a while now. 

Back in March of 2021 we started at a mountain pass called Passwang in the Jura hills of northwest Switzerland, walking eastward along a crest trail down to the village of Waldenburg in Canton Baselland. (Photos HERE). On our way to Waldenburg in the valley bottom, we saw a castle ruins on the hills to the east, and determined we would walk there one day.

On this day, we started as high up as the bus would take us on the south side of the Jura range (at the Allerheiligenberg Klinik above Hägendorf near Olten) and walked about 10 kilometers in a typical Jura landscape of small valleys and cliffs called "Flue", ending by walking along the Gerstelflue crest to the Waldenburg Castle ruins. It was a relatively easy walk, even the short craggy section along the narrow crest at Gerstelflue.

As it turns out, this trail is part of an educational trail documenting the defense fortifications set up here during WWI, with extensive bunkers, trenches and look-out points. Many panels along the way give lots of information about this bit of local history.

(Translated from the website: https://www.fortifikation-hauenstein.ch:  "The Hauenstein Fortifications in the Baselbieter and Solothurn Jura formed the eastern northern barrier in Switzerland's defense during World War I. The chain of fortifications and defensive works is over 42 kilometers long and forms a protective semicircle around the railway town of Olten...... The Hauenstein fortification was designed to accommodate a garrison of 45,000 soldiers and 6,500 horses. Its mission was to push back or neutralize French or German troops north of the Jura Mountains in the event of a breach of the border into neutral Switzerland, if necessary by force. ")   

On the south side of the Jura range, we take a bus from Hägendorf (near Olten) to the Allerheiligenberg Klinik, the highest point the bus goes. After a 2-hour trip from home, we started there at 10 a.m. After a 15-minute walk up to the first pass, we should be able to see the Alps to the south, but unfortunately, today's visibility is not nearly as good as the day before.

Starting at Allerheiligenberg at 10:00, we started on a section of trail we had done before (when we headed via Belchenflue on "Trail no.5: Jura Crest Trail", photos HERE), and headed north via Spitzenflue, Geissflue, Lauchflue and Gerstelflue to Waldenburg, where we caught a bus at 3 p.m. 

From the bus stop, it was a relatively short 15-minute walk to the highest point before crossing to the north side of this first crest, where we walked on a narrow forest trail in the shade for about 10 minutes. 

After crossing another small "pass", we now look down one of the many little valleys. This location is called Gwidem, and the town at the bottom of this valley is Langenbruck. 

Crossing the next "pass" into the next valley, there is still a lot of snow here on the north side of the range called Dürstelberg. The range at the back by the arrow is the one we will walk on the final stretch to the west.  The mountain in the center with the distinctive cliffs is called Ankenballen. 

Looking down the next side valley now as we head toward the next pass alled the Chilchzimmersattel, where a vehicle road crosses from the east to head down this valley. 

One of many military bunkers we run across in our hikes in Switzerland. This is near the start of the 3-kilometer section of trail with the theme "Commemorative Trail: First World War".

At 11 a.m. we found the perfect bench for a small snack break. 

This was the view we had from the little bench! 

At the Chilchzimmersattel Pass, the sign indicates another two hours to Waldenburg, but it was longer than that!

View eastward from the Chilchzimmersattel Pass

For the next 2½ kilometers, the trail is part of a newly-created (2024) themed trail called "Commemorative Trail: First World War". There were many defense trenches here. 

Following the old trenches from WWI era. 

Panels give information about the defense systems here, including photos of what it looked like at the time of the First World War. 

Up ahead we can see the crest that we are going to walk at the end of our hike just before reaching the ruins of the Waldenburg Castle. 

"View of Ankenballen". This photo is an original from the WWI years, and shows a defense line here. 

"View of Ankenballen" today. Over 100 years ago, there was a defense line here. 

Close-up view of Ankenballen. These small mountain ranges here all have vertical cliffs and interesting stone towers, and are called "Flue"

Nice comfortable trails

This large clearing called Schattenbergweid is the top of a vertical dropping cliff on the right, called Geissflue. 

Taking a detour to the edge of the clearing to check out the view to the east. (This here is looking west). 

The view from this part of the edge of the cliff was slightly blocked by trees. 

Fantastic view from the edge of Geissflue over the rolling hills of Canton Baselland. (Direction Hauenstein). On the left you can see part of the vertical cliffs of the Geissflue. It looks like that below where we are standing as well.

Some early spring greenery. The bees were already busy here. An Internet search tells me the plant is called "Stinking Hellebore", what a lovely name! Also from Wikipedia: "Despite its common name, it is not noticeably malodorous", but apparently all parts of the plant are poisonous. 

More sun-dappled forest trails

Here we came to a clearing called "Lauch" (below Lauchflue), and being 12:15 now, we sat on the grass and had our sandwiches. We stayed here for a bit until another group of four people had the same idea and sat nearby. We are not so fond of chatty people in the mountains!

At the highest point of the Lauchflue we discovered this bunker-type building. It is the Lauchflue Observation Post, built in 1914 by the Swiss Military. Locally, it is known as the "Little Tank Tower". (Panzertürmli)

A diagram shows a cross-section of what the inside of this observation post looked like. We were also able to walk around the inside. 

At the top of "The Little Tank Tower", we get a superb view of the landscape to the north. Unfortunately the air was a bit hazy, but for sure you can see across into the Black Forest in Germany from here. 

The hills to the west, and north of the final Flue which we are walking along on the left: Gerstelflue. 

We could also see far to the south to the Alps, slightly more visible now than when we started on the hike. 

The rest of our hike is now along the crest of this range, heading westward. 

The sky had become somewhat overcast for this part of the hike, but we didn't mind as the trail was quite interesting. 

This short piece seems to be problematic for some people, but we like this kind of "challenge". This is a spot called Rehhag. 

Once in a while the trees thin out and we get a view. 

The trail follows the vertical north face of the Gerstelflue. 

Everywhere interesting rock formations

This was a very cool spot with interesting rock formations. 

Very neat rock formations here. This is called the Schlossberg (Castle Mountain, as the Waldenburg Castle is nearby).

First look at the Waldenburg Castle Tower as we approach the entrance from the north side. 

Inside the castle grounds

Entering the castle gate on the north side, and heading to the tower entrance. 

It was fun climbing up to the top of the tower, on this narrow wooden staircase, and later stone steps in a very narrow passage and then a wooden ladder-type. 

The sun came out again here at the end of our hike, and we are enjoying some time up here on the tower of the Waldenburg ruins. 

Panorama view to the north from the castle tower. 

To the north is a town called Oberdorf. The town of Waldenburg is at the foot of this mountain to the west and south, although the train station (the goal of our hike) is on the bottom left. There were Carnival activities in this region this weekend, and we could hear the Carnival Parade and music from up here, but could not see the parade. 

I'm not sure what Urs is studying there... probably the train schedule.

Directly to the east is that range (Geissflue, Schlossberg) where we had come from, although most of the trail was on the north side of the range. 

To the west below the end of this mountain is the village of Waldenburg. When we did the hike from the west in March of 2021 (photos HERE), we came along the crest and past the mast/pole on the mountain directly across from here. That's when we saw the castle ruins here, and decided to come back some time. 

(This is the tower we saw from across the valley on our hike in 2021, at which time we decided we wanted to walk there some time.)

View from the tower directly onto the grounds of the castle ruins below. 

Final stop will be the Waldenburg train station below, at the arrow, descending through that little community on the north side of the castle. (We did not go down via the old town of Waldenburg, as we had a good look at the main street there at the end of our 2021 hike). 

Fun stairs inside the tower

Back down in the castle grounds. There was a family making a campfire, and since I don't like the smell of wood fire smoke, we didn't stay any longer. 

Leaving the castle grounds. 

As it's now 14:46 and the bus we want to catch leaves at 15:03, we had to rush down to the train station and just made it there as the bus pulled in. No time for photos!

This is what our hike looks like on Google Satellite Maps

From Waldenburg, the bus takes us via Langenbruck to the train station in Balsthal. There are several other castle ruins here, in particular that beautiful one guarding the cleft between those two peaks. It is called Neu Falkenstein, a site we have not yet visited!

Close-up view of the Ruins of Neu Falkenstein Castle. 

The castle guards the entrance to that valley behind the cleft. 

From Balsthal, a small train takes you to Oensingen (then to Zurich and home, altogether just over two hours) where the Oensingen Castle (Neu Bechburg) dominates the hillside. We visited this beautiful castle once on a hike from Balsthal to Oensingen in May 2020, those photos are HERE. 

All the hikes we have done in the area around Balsthal/Langenbruck/Waldenburg in northwestern Switzerland. 

Location of our hike within Switzerland.