The Lluta originates at the confluence of the Quebrada Caracarani (which rises from the slopes of the Tacora volcano) and the Azufre River, at an elevation about 3,900 m asl. Along its first 36 km, the river flows southeast and then slowly begins to turn towards the west. In its descent to the lower elevations of the valley, the river starts to run through a canyon carved by the same river in rhyolite tuffs and other sediments scarcely joined.