Chiemsee is a municipality in the district of Rosenheim in Bavaria in Germany, named after the lake Chiemsee. It is Bavaria's smallest municipality by area and the second smallest by population.
The municipal area comprises not the lake itself but the islands of Herrenchiemsee with its Palaces, Frauenchiemsee and the uninhabited Krautinsel. While the island of Herrenchiemsee with 2.38 km² is by far the largest, most of Chiemsee's inhabitants live on 0.15 km² Frauenchiemsee.