Festung Heldsberg

Useful Information

Location: St. Margrethen. Located in a foothill between St.Margrethen and Au, parking at the restaurant Schäfli at the highway, 10 minutes walk to the fortress.
RTB bus from the train stations St. Margrethen and Heerbrugg to stop Heldsberg.
Open: APR to OCT Sat 13-18.
Groups (12+): all year after appointment.
Fee: Adults CHF 10, Children (6-16) CHF 5, Guided Tour CHF 30.
Groups (12+): Adults CHF 7, Children (6-16) CHF 3.50, Guided Tours CHF 20.
Classification: SubterraneaWorld War II Bunker
Light: LightIncandescent Electric Light System
Dimension: L=1,000 m.
Guided tours:  
Address: Festungsmuseum Heldsberg, 9430 St.Margrethen, Tel: +41-71-733-4031. E-mail: contact
Postanschrift: Festungsmuseum Heldsberg, 9444 Diepoldsau.
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
Please check rates and details directly with the companies in question if you need more recent info.


1938 begin of planning.
1939 start of constructions.
1940 completed.


The Festung Heldsberg (Heldsberg fortress) is a defensive fortification at the eastern entrance to Switzerland. Here the wide and flat valley of the Alpenrhein opens to the north, towards Germany and Austria. This is the upper part of the Rhine river, which flows into the Bodensee (Lake Constance). For some kilometers the Swiss border to Austria is formed by the Rhine river, not by a mountain ridge, and so in case of an invasion this would have been the ideal geography to enter the country. A second possibility would have been an attack across Lake Constance, and this fortress also protected this border.

At the begin of World War II the Swiss government planned various fortifications to protect the borders wherever they are not protected naturally by steep mountains. So this underground fort was planned before the war, after Austria was annexed by Germany on 12-MAR-1938, at this strategic location and built during the early years of the war. The power of the fortress was known to the Germans, so an internal report called Operation Tannenbaum (operation Christmas tree) contained the recommendation to avoid this area in case of am attack against Switzerland, because of the fortress.

The fortification is a 1,000 m long tunnel which had room for some 200 soldiers. It is protected by four 7.5 cm cannons and seven machine guns. 21 more machine guns were located in satellite bunkers, where 400 more soldiers were stationed. It was also equipped with mine throwers and various anti-tank weapons. The area was covered with barb wire and anti-tank obstacles.

The bunker is today used as a museum for this kind of fortresses. It shows anti-airplane and anti-tank canons, heavy infantry weapons and ammunition from World War II. There is an exhibition of hand held weapon development in Switzerland during the last century and a collection of ammunition cross sections. A part of the exhibition shows historic and contemporary communication equipment. And finally there is an exhibition of binoculars, sighting mechanisms, and telescopic sights. There are also lamps, gas masks and other equipment. The exhibitions were donated by locals.