Trojmezná mountain ("Mount of Three Landmarks" - 1,361 m) lies on the Czech-German border in the Šumava mountains (Bohemian Forest). The mountain has two peaks: a higher one is on the Czech side and a lower one on the German side, which is called Bayerischer Plöckenstein (1,358 m).

This mountain is a part of the nature reserve Trojmezná Hora ("Three Landmarks Mountain") and it is an important peak of the edge of the Šumava mountains. The top offers nice views of the surroundings and the Alps. Several seas of stones can be seen on hillsides.
Near the top of the mountain (in the height 1,321 m) there is a place called Trojmezí ("Three Landmarks Place", German "Dreieckmark") - the convergence of borders of the Czech Republic, Austria and Germany. In this place there is a trilateral hoarstone.

The peak is accessible along the red marked sierra trail from the small village Nové Údolí (about 12 km south-west of the town Volary near the Czech-German border). The path leads over the peaks of Třístoličník ("Three Stools Mount") and Trojmezná mountains (about 10 km) to the top of Plechý mountain.