Lake Constance or Lake of Constance (German and Alemannic Bodensee) is a large lake on the Rhine between Germany, Switzerland, and Austria. The freshwater lake sits at 395 m above sea level and is Central Europe's third largest, after Lake Balaton and Lake Geneva. It is 63 km long, and at its widest point, nearly 14 km. Lake Constance was formed by the Rhine Glacier during the ice age. The Rhine, the Bregenzer Ache, and the Dornbirner Ache carry sediments from the Alps to the lake, thus gradually decreasing the depth of the lake in the southeast. The name probably derives from the Bodensee place names Bodman. This, on the western end of Lake Überling place in the Middle Ages for a time as a Frankish royal palace, Alemannic duke seat and mint of national importance, so that the name could have been transferred to the lake (lake, located at the Bodman - Bodman-Lake). Riparian countries are Switzerland (cantons of Thurgau, St. Gallen and Schaffhausen), Austria (federal state Vorarlberg) and Germany (Federal States of Baden-Württemberg and Bavaria).