Located 10 km from the Panamericana Sur Highway, 40 km from Osorno and 895 km from Santiago. It has a population of 23,265. It is located on the bank of the Llollehue River , and has the name La Unión because it is here that the Llollehue and Radimadi Rivers are joined, which then flow into the Bueno River.

It was founded in 1821 as a center for farming services for Los Llanos, north of the Bueno River. The city was known for its breweries, production of leather goods, linen factories and mills. Nowadays you can still find examples of architecture in the German style.

In this sector you can visit the Alerce Andino Natural Monument and the Bueno River, amongst other things.