Untersee

Untersee, meaning "lower lake" in German, refers to the western portion of Lake Constance (Bodensee), the large freshwater lake at the northern foot of the Alps that is shared by Germany and Switzerland (with Austria nearby in the broader lake system). The Untersee lies to the west of what is commonly called the Obersee, and together these parts form the full lake.

Geographically, the Untersee is bordered mainly by the Swiss cantons of Thurgau and St. Gallen and by the German state of Baden-Württemberg. It includes the island of Reichenau, a notable historic site, and the lakeside towns such as Kreuzlingen and Konstanz on its shores. The region is characterized by a mix of urban centers, historic towns, and agricultural landscapes, with ferry and boat connections linking communities around the shoreline.

Hydrologically, the Rhine River is the principal outflow of Lake Constance, and the lake is fed by Alpine rivers and tributaries from the surrounding regions. The Untersee forms part of this larger hydrological system, contributing to the lake’s water balance and supporting regional tourism, fishing, and transport.

Culturally and historically, the Untersee region has long been important for trade and settlement around Lake Constance. The island of Reichenau on the Untersee hosts a UNESCO World Heritage Site featuring a medieval monastery complex. The area remains a popular destination for boating, hiking, and sightseeing.