Cerro Ventana, Mountain peak in Sierra de la Ventana range, Buenos Aires Province, Argentina.

Cerro Ventana is a 1,136 m peak in the Ventania range, Tornquist Partido, Buenos Aires Province, within Ernesto Tornquist Provincial Park. Near its summit a collapse formed a natural hole 9 m high, 5 m wide and 12 m deep, the opening that gives the mountain its name.

The mountain was documented by Charles Darwin during his voyage aboard the Beagle, who recorded its geological features in his scientific notes. This early observation helped establish the site's importance for understanding South American geology.

The name comes from the 9-metre-high, 5-metre-wide opening near the summit, formed by a landslide. Since 7 December 1995 the peak has been protected as a natural monument under Buenos Aires provincial law 11750. Access on foot without a guide is currently disputed, and a petition to restore self-guided ascents has gathered over a thousand signatures.

The mountain can be reached via Provincial Route 76, with the nearest town being Villa Ventana which serves as a convenient base for visitors. Early morning arrival is recommended to have adequate daylight for the hike and to explore the area comfortably.

The name comes from a collapse near the summit that left a hole 9 m high, 5 m wide and 12 m deep, at 1,136 m above sea level. Since 7 December 1995 the peak has been protected as a natural monument under Buenos Aires provincial law 11,750.