Piz Bernina separates two glacial valleys, the Tschierva Glacier on the west and the Morteratsch Glacier on the east. The waters flowing on both side of the mountain end up in the Inn River running northeast through Engadin. South of Piz Bernina the watershed separates the drainage basins of the Danube (Black Sea) and the Po River (Adriatic Sea). The summit of Piz Bernina is the culminating point of the Danube drainage basin. Politically, it is split between the municipalities of Samedan and Pontresina.