Which U-shaped river in the Atacama Desert is Chile's longest river?

The U-shaped river in Chile’s Atacama Desert and the country’s longest river is the Loa River.

The Loa runs for about 440 km through northern Chile’s Antofagasta Region. Its headwaters rise on the Andean slopes near Miño Volcano, after which the river travels across the high plateau, bends south and west, then turns north before curving back toward the Pacific. That broad, looping route gives it its distinctive U shape.

The river is the principal watercourse of the Atacama Desert, one of the driest places on Earth. It passes near Chiu Chiu, through the mining city of Calama and by Quillagua before cutting through the Coastal Range in a deep canyon. It reaches the Pacific south of Huanillos.

The Loa is not simply a desert channel: Andean tributaries such as the San Pedro de Inacaliri and Salado rivers feed its upper basin. Its lower waters become brackish, and mining, agriculture and water extraction have placed pressure on the river. Aconcagua, Maipo and Biobío are important Chilean rivers, but none is longer than the Loa.