Unterseen is a historic town[3] and a municipality in the Interlaken-Oberhasli administrative district in the canton of Bern in Switzerland.

Both municipalities are located on the flat alluvial land among steep mountains, which is also called the Bödeli.

[4] Along with Interlaken, Unterseen is an important tourist center in the Bernese Highlands, and from the town one can see the mountains Eiger, Mönch and Jungfrau.

The area was known as Interlacus by 1133 when Interlaken Monastery was founded on the opposite side of the Aare.

The city of Unterseen was founded on 13 July 1279, when King Rudolf I von Habsburg granted Baron Berchtold III of Eschenbach-Oberhofen permission to build a stronghold between the two lakes.

[5] It was built by the secular nobles of the area to limit the growing power of the Monastery and to control a bridge over the Aare.

The young town was put in an ongoing conflict with the Interlaken Monastery and early on sought protection from Bern.

[5] During the Reformation the town turned against Interlaken Monastery and did not join the Berner Oberland uprising.

In 1470 Unterseen was burnt down for the second time and Bern undertook the reconstruction with the town house in the center.

[5] After the establishment of the Helvetic Republic, Unterseen became a center of resistance against the reestablished Bern feudalism.

In the early 19th century, the town wall and moat were broken down and the gate house was demolished in 1855.

In the burgeoning tourism of the middle of the 18th century, Unterseen played an important role, which has since been taken over in large part by Interlaken.

It consists of the historic town of Unterseen and its urban village-like settlements, rural parts closer to the Lake Thun including several camping sites, some with beaches, a golf course on the Unteres Stadtfeld, and scattered settlements and woods on the nearby steep mountainside of Dälebode, Chienberg and Harder (Vordere Harder, Hintere Harder, Luegiwald).

[8] The blazon of the municipal coat of arms is Or a Semi Ibex rampant couped Sable langued Gules.

[12] Most of the population (as of 2000[update]) speaks German (4,636 or 89.1%) as their first language, Portuguese is the second most common (110 or 2.1%) and Italian is the third (105 or 2.0%).

The historical population is given in the following chart:[5][15] The old city of Unterseen and the ruins of Weissenau Castle are listed as Swiss heritage site of national significance.

The entire town of Unterseen is part of the Inventory of Swiss Heritage Sites.

In the tertiary sector; 174 or 12.8% were in wholesale or retail sales or the repair of motor vehicles, 237 or 17.4% were in a hotel or restaurant, 28 or 2.1% were in the information industry, 31 or 2.3% were the insurance or financial industry, 72 or 5.3% were technical professionals or scientists, 55 or 4.0% were in education and 588 or 43.3% were in health care.

[12] From the 2000 census[update], 831 or 16.0% were Roman Catholic, while 3,403 or 65.4% belonged to the Swiss Reformed Church.

This is followed by three years of obligatory lower Secondary school where the students are separated according to ability and aptitude.

Following the lower Secondary students may attend additional schooling or they may enter an apprenticeship.