Thun (French: Thoune, German: [çu̯oːn]) is a city and municipality in the administrative district of Thun in the canton of Bern in Switzerland with about 42,136 inhabitants (near 90,000 in the agglomeration), as of 1 January 2006. It is located where the River Aare flows out of Lake Thun (Thunersee), 30 km south of Bern. Besides tourism, machine and precision instrument engineering, the largest garrison in the country, the food industry, armaments and publishing are of economic importance to Thun.
The centre of Thun is located on the River Aare, just downstream of the point where that river flows out of Lake Thun, and encompasses both banks of the river and an island between. The city covers an area of 21.6 km2 (8.3 sq mi), with the city boundaries reaching up to 4 km (2.5 mi) from the city centre. The city ranges in altitude between about 560 m (1,840 ft), in the city centre, and 1,170 m (3,840 ft), on its eastern boundary. Of the city's total area, 32.1% is used for agricultural purposes, while 19.7% is forested. Of the rest of the land, 45.6% is settled (buildings or roads) and the remainder (2.5%) is non-productive (rivers, glaciers or mountains).