Aggenstein, Mountain in Tannheim Mountains, Austria and Germany

Aggenstein is a limestone mountain in the Tannheim Mountains on the border between Austria and Germany, rising to 1986 meters. Its northern face drops away steeply while the southern slopes descend more gradually and are covered with alpine meadows.

The Aggenstein lies on the border between Bavaria and Tyrol, in the Bavarian part of the Tannheim Mountains a few kilometres south of Pfronten. Its prominence is at least 266 metres and its isolation 1.8 kilometres, with the Brentenjoch as reference peak. The Bad Kissinger Hut, an Alpine Club hut, serves as the main base on the routes to the summit.

The Aggenstein lies on the border between Bavaria and Tyrol, and the state border runs across its summit. The Bad Kissinger Hut below the peak, run by the German Alpine Club, serves walkers arriving from both the Pfronten and Grän sides. The mountain's south wall plates and adjoining ridges are used as a via ferrata-style climb, graded II to VI and well secured with cables.

From Grän-Enge at the Lumberg car park, the route runs via Seebach and the Bad Kissinger Hut to the summit in about 2.5 hours; a longer variant adds the Seebenalpe and the Tannheimer Höhenweg (about 3 hours). From Grän via the Füssener Jöchl and Tannheimer Höhenweg it takes about 4.5 hours, with cable-car support possible. The Bad Kissinger Hut has a climbing garden beside it.

The Aggenstein's isolation is just 1.8 kilometres, with the Brentenjoch as its reference peak, and its prominence is at least 266 metres. Its south wall plates and the adjoining ridges are bolted for climbing at grades II to VI, while the north and west walls, graded III- to VIII-, are rarely climbed and often wet and crumbly.