Chiemsee is a freshwater lake in Bavaria, Germany, near Rosenheim. It is often called "the Bavarian Sea". The rivers Tiroler Achen and Prien flow into the lake from the south, and the river Alz flows out towards the north. The Alz flows into the Inn which then merges with the Danube. The Chiemsee is divided into the bigger, north section, in the northeast, called Weitsee, and the Inselsee, in the southwest.
The Chiemgau, the region surrounding the Chiemsee, is a popular recreation area.