Pena Corneira, Nature reserve in Leiro, Spain

Pena Corneira is a 998-hectare natural monument shared by Carballeda de Avia, Leiro and Avión in O Ribeiro. Its granite massif, part of a batholith about 300 million years old, forms ridges, domes, depressed corridors and boulder fields. At the summit stands the ten-metre vertical rock that gives the place its name.

The protection process began in January 2007 and concluded on 20 December 2007, when Pena Corneira was declared a Natural Monument; the announcement appeared in the Diario Oficial de Galicia on 28 January 2008. The granite massif itself is a Hercynian batholith roughly 300 million years old, 18 km north-south and 7 km east-west.

The granite outcrops carry popular names recorded in local tradition: Outeiro da Campá, Outeiro dos Forniños, Outeiro do Lagarto and Outeiro da Bañeira do Demo. The summit crag, a ten-metre vertical rock, serves as a visual landmark alongside the Faro das Laceiras above the Avia valley.

Visitors can explore the reserve using marked hiking trails, with the main access point at A Ponte das Poldras in Leiro. Good footwear and proper equipment are important since the terrain is steep and rocky throughout.

At the summit stands the Pena Corneira itself, a vertical crag ten metres high that serves as a visual landmark above the Avia valley, alongside the Faro das Laceiras. Erosion has scattered granite boulders over the hill in the shape of large balls and odd forms, giving names to spots such as Outeiro da Campá, Outeiro dos Forniños, Outeiro do Lagarto and Outeiro da Bañeira do Demo.