
At the 'Lake Constance' the three states of Germany, Austria and Switzerland meet - a tripoint without any sign. The Waymark is located in Vorarlberg, Austria.
Tripoint Germany / Austria / Switzerland

There is still no precise definition of the territorial affiliation of Lake Constance and thus it's interpreted in different ways by the different countries. Only one thing is certain: somewhere in the area of ??the so-called Obersee of Lake Constance exists the Tripont of the three states Germany, Austria and Switzerland! The most likely and most associated point is near the coordinates N 47° 32.000 E 009° 38.500. Since there are different views of the territorial allocation, there are regularly different calculations of the tripoint, but an exact marking or even a sign is not yet available and will probably never exist.
Condominium
According to the Austrian view the Obersee of Lake Constance is a condomnium - with no borders between the neighboring countries, but the sovereign tasks of the neighbors of Germany, Austria and Switzerland are shared together. Austria consider the entire Obersee (probably without the Überlinger See) as a condominium, with the exception of the stockpile, the upper section of the river up to 25 meters of water depth. Whereas Switzerland - as usual in the case of inland waters - preferred a division in the middle distance from the banks. Concerning the Constance Basin and the so-called Untersee, there are corresponding contractual agreements between Switzerland and Germany.
Territorial affiliation
The neighboring states of Lake Constance are Switzerland (cantons of Thurgau, St. Gallen and Schaffhausen), Austria (federal state of Vorarlberg) and Germany (federal states of Baden-Württemberg and Bavaria). Since 1972 the countries and cantons bordering the lake have been cooperating in the bodies of the 'Internationale Bodenseekonferenz' (IBK). The aim is to preserve, promote and promote the regional territory as an attractive area for life, nature, culture and economy.
The Constance 'Tunnel' in the Obersee, the 'Seerhein' as well as the Untersee are defined and clearly divided by border agreements between Baden and Switzerland (20th and 31st October 1854 as well as 28th April 1878) and between the German Reich and Switzerland (24. June 1879). The Überlinger See is completely part of the German territory. Since the 16th century has been a complicated frontier in the western section of the Obersee between Konstanz and the present Kreuzlingen, from the beach to the Constance 'Tunnel', which was fixed with the agreement of 1878.
The rest of the Obersee remains as the only area in Europe where the boundaries between the neighbor states never have been established. There are different legal conceptions, all of which are traced back to customary law. The segregation which can often be seen on maps, is based on the so-called real-dividing theory, which 32% of the lake area is accounted for by Switzerland and 9.7% by Austria. The other common opinion is the theory of the stables, according to which the territory of the upper sea is a communal territory of all the neighboring countries, outside of the shore as a condominium.
source: [DE] Wikipedia
