The border of the Allgäu Alps in the west, where it transitions to the Bregenz Forest Mountains is not orographically distinct. The Alpine Club classification of the Eastern Alps, published in 1984, draws the boundary as follows: from Au-Rehmen along the Rehmerbach upstream to the Stogger Saddle. Then it descends, following the Osterguntenbach, the Schönenbach and the Subersach to its confluence with the Bregenzer Ach and along this river to where it joins the Weißach or event to Lake Constance.