Cerro Bayo is a complex volcano on the northern part border between Argentina and Chile.

The main volcano face is located on the Argentine side, thought the summit of the complex is just west of the border, in Chile.

The 5,401-metre (17,720 ft) high summit is the source of two viscous dacitic lava flows with prominent levees that traveled to the north.

Elemental sulfur can be found at Bayo,[1] both in the form of high-grade massive deposits and as extinct fumarole chimneys.

[4] The youngest dated rocks are about 23,000 years old;[5] in 2007 a steam eruption were observed by researchers investigating nearby salt pans such as Salar Ignorado.