Fort Biehler, named after the head of the Prussian engineering corps Hans Alexis von Biehler, was built between Kastel and Erbenheim on the Petersberg in 1880-84 to reinforce the former fortress of Mainz. The facility was used as a barracks until 1910, when a final extension was made with a training area for the newly established Pioneer Battalion 25 in Mainz.

During the First World War, replacement troops were trained on the site for their deployment at the front. After the war, Fort Biehler was occupied by French troops until 1927. When they withdrew, the site was razed; in the 1930s, the remaining building materials were used to construct the "Fort Biehler" housing estate. After the reoccupation of the Rhineland in 1936, the remains of Fort Biehler were reactivated and used as a military training area. During the Second World War, the site served as a temporary air raid shelter. After the end of the war, American troops filled the underground parts of the complex with rubble.

Today, only the remains of the former barracks, a section of the main tunnel and a remnant of the left flank wall give an idea of the dimensions of the former fort. The site is still not freely accessible today. The Civil Protection Service has been operating its training grounds on a large part of the site since 1956. The rest is privately owned.