The Karwendel is the largest mountain range of the Northern Limestone Alps. The major part belongs to the Austrian federal state of Tyrol, while the adjacent area in the north is part of Bavaria, Germany. Four chains stretch from west to east; in addition, there are a number of fringe ranges and an extensive promontory (Vorkarwendel) in the north.

The Isar is a river in Austria and in Bavaria, Germany. Its source is in the Karwendel mountain range of the Alps. The Isar river enters Germany near Mittenwald and flows through Bad Tölz, Munich, and Landshut before reaching the Danube near Deggendorf. With 295 km length, it is among the longest rivers in Bavaria. It is Germany's second most important tributary of the Danube.