Fort Biehler, Military fortification in Wiesbaden, Germany

Fort Biehler is a fort on the Petersberg in Wiesbaden, built 1880–1884 as Fort Petersberg and renamed in 1885. It follows the Biehler-Fort standard design of the Prussian Engineering Corps. Demolition in 1927 left ruins; stone from them was used for the Siedlung Fort Biehler housing estate nearby. The grounds now serve civil defense exercises.

Fort Biehler was built from 1880 to 1884 on the Petersberg, following a design drafted by the Prussian engineering corps in April 1878. On 30 April 1885 it was renamed after Hans Alexis von Biehler, who had left his post as chief of that corps the year before. The last major conversion came in 1910, when a practice work for Pioneer Battalion 25 was installed. Under Article 180 of the Treaty of Versailles the fort was disarmed, and demolition ran from April to August 1927.

The fort shows how Prussian military engineers of the late 19th century designed defenses to handle both distant attacks and close-range fighting. The remaining walls still reveal the building methods they used.

Fort Biehler lies on the Petersberg near the Erbenheimer Warte in Wiesbaden; the grounds have served the civil defence service for exercises since 1956 and are not freely accessible. A local initiative has worked since 1998 to keep the fort remains, which are not under monument protection. Arrange any visit with the responsible authorities in advance.

The fort's rubble was not wasted: in 1930 the Dyckerhoff cement works bought the ruin and gave the debris to the city of Mainz, which used the stones to build the Fort Biehler settlement for the unemployed nearby. Residents later used the surviving vaults as makeshift air-raid shelters in the Second World War.