is a town in the Potosí Department
in the south of Bolivia
. Founded in 1890 as a trading post, the town has a population of 10,600 (2006 official estimate). The town has an extensive street-market. It lies at the edge of an extensive plain at an elevation of 3670 meters above sea level, with more mountainous country to the east. There is little agriculture in the area, because water supplies are scarce and somewhat saline. Today the town's primary function is as a gateway for tourists visiting the world's largest salt flats - the Salar de Uyuni
It is an important transport hub, being the location of a major railway junction. Four lines join here, respectively from La Paz (via Oruro), Calama (in Chile), Potosí, and Villazón (on the Argentine border, where the line now ends).
One of the sights in Uyuni is the train cemetery - filled with old, rusting steam locomotives.