Diesburg, Mountain peak in Thuringia, Germany.

Diesburg is a 711.8-metre mountain of the Hohe Geba massif in the Kuppenrhön, in the Thuringian Rhön Biosphere Reserve. It is a volcanic-origin basalt cone, and stone remains of a Celtic rampart from the La Tène period, around the 3rd century BC, lie on the summit.

The Diesburg is a volcanic basalt cone of the Hohe Geba massif. On its summit are the remains of a stone Celtic rampart from the La Tène period, around the 3rd century BC. The mountain lies in the Rhön Biosphere Reserve in the Schmalkalden-Meiningen district of Thuringia.

The mountain sits within the Biosphärenreservat Rhön, a protected area that the region actively maintains as a place for nature observation and environmental stewardship. Visitors experience a landscape shaped by local communities and conservation efforts working together.

Two marked long-distance trails cross the Diesburg: the Rhön-Rennsteig trail links it with Aschenhausen and the Gebaberg, and the Milseburgweg (HWO3) also passes over the summit. The mountain lies between Gerthausen, Wohlmuthausen and Helmershausen, all in the Rhönblick municipality, with Meiningen about 14 km to the west-northwest.

The summit holds the remains of a Celtic stone rampart from the La Tène period, around the 3rd century BC. The mountain is volcanic in origin, with a basalt cone, and lies in the Rhön Biosphere Reserve within the Geba-Tuften–Diesburg FFH area. Long-distance paths cross it, including the Rhön-Rennsteig trail linking Aschenhausen and the Gebaberg.