Lake Constance is a lake on the Rhine at the northern foot of the Alps, and consists of three bodies of water: the Obersee ("upper lake"), the Untersee ("lower lake"), and a connecting stretch of the Rhine, called the Seerhein. The lake is situated in Germany, Switzerland and Austria near the Alps. Specifically, its shorelines lie in the German federal-states of Bavaria and Baden-Württemberg, the Austrian federal-state of Vorarlberg, and the Swiss cantons of Thurgau and St. Gallen. The Rhine flows into it from the south following the Austro-Swiss frontier.