Unterseen is a historic town and a municipality. In the interlaken-Oberoi administrative district in Bern's campus of Switzerland. The literal meaning of Eutreson is Lower Lake, which is right, because the untreated Chinchburg is located on the flat area on the eastern edge of the Thun Lake between the two caves Lombunk. Aarey in the north and south, both of which flow in Thun Lake. Although the historic city is found mainly on the northern coast of Aare, which flows here from Brijen Lake to Thoon Lake hence the Lower Lake. There is only Interlaken city in Aarey.
Both the municipalities are situated on the plain alluvial land between the steep hills, also called Bodelli. Unterson is an important tourist center in Bentigh Highlands, and any mountains from the city can see Eger, Monch and Jungfrau. One of the oldest sculptures of a settlement in the area is the Neolithic tools scattered. During the second century AD, a Roman cemetery was built in the area.
An early Middle Ages cemetery shows that there was a settlement in the area and at least three forts were built in the area till the higher middle age. Until 1133 this area was known as Interlacus, when Interlaken Monastery was set up opposite of Aarera. Interlacan village grew up from monastery in the next years. By 1239 it was known as Villa Inderlappan and in 1280 it was Indarsal Indrappan. Untreisen City was founded on July 13, 1279, when King Rudolf I von Habsburg allowed Baron Barktold III to make Aschenbeck-Oberholfen a stroke.