Parc naturel Macizo de Peña Cabarga, Nature park in Cantabria, Spain.

The Macizo de Peña Cabarga is a nature park in Cantabria featuring limestone formations, deep gorges, and dense forests across the landscape. The terrain consists of sharp rock edges covered in lush vegetation and valleys carved by water and erosion.

Iron mines on the massif supplied the La Cavada and Liérganes ironworks, Spain's first steelworks and cannon foundry, between the 17th and 19th centuries. From the late 19th century, Spanish and English concessions extracted iron oxide nodules in open pits; the washed ore was shipped from the El Astillero loading dock, still standing, to Cardiff. Altos Hornos de Vizcaya bought the mine in 1951, and the last workings closed in 1989.

The name Peña Cabarga comes from the limestone crag that dominates the massif. Iron ore from these slopes fed the La Cavada and Liérganes foundries, Spain's first steelworks and artillery factory, from the 17th to 19th centuries. Ore washed here was shipped from the El Astillero quay, whose loading dock still stands, to Cardiff.

The main access is the CA-412 regional road near Heras, between Solares and El Astillero; other approaches run through La Concha de Villaescusa and Socabarga. The summit, Pico Llen at 569 m, is reached on foot or by the road to the communications towers. The karst of Cabárceno lies within the massif, and the old El Astillero ore-loading wharf survives on the bay shore.

The park's highest point is Pico Llen, at 569 metres, which serves as a lookout over the Bay of Santander. Within the massif lies the Cabárceno karst, a reddish limestone formation dissolved by water and declared a Point of Geological Interest. Iron ore was mined here in opencast workings until the Cabárceno concession closed in 1989.