Cerro Horcón de Piedra, Mountain summit in Metropolitan Region, Chile.

Cerro Horcón de Piedra is a 2,048-metre summit in the Chilean Coastal Range, southwest of Laguna de Aculeo in Melipilla Province. Its easternmost top is crowned by a rock tower that requires a short scramble. The upper slopes hold native roble and peumo woodland, and old stone pircas stand on a plateau below the summit.

Cerro Horcón de Piedra was declared a Santuario de la Naturaleza by decree No. 517 on 30 December 2009, together with Altos de Cantillana and Roblería Cajón de Lisboa. A second decree, No. 28 of 26 July 2011, issued by the Ministry of the Environment, confirmed the protection. The designation covers the summit and its native forest of roble and peumo on the slopes.

The name Horcón de Piedra refers to the rocky tower crowning the easternmost summit, which needs a short scramble to reach. On the way up, hikers pass old stone pircas and a small spring on a plateau at 1,462 m, and cross a mature oak forest about ten minutes beyond it.

Visitors should bring sturdy hiking gear and check weather conditions before heading up, since conditions can change rapidly. The journey requires physical stamina and good planning to stay safe.

The true summit is the easternmost crag, crowned by a rock tower that needs a short scramble; lower rocks to the west look like the top from below. From the summit, the Pacific and the bay of San Antonio are visible, and at night the lights of Santiago de Chile.