The Sierra del Escudo de Cabuérniga is a mountain range located between the Cantabrian Mountains and the Bay of Biscay, inside the autonomous community of Cantabria, Spain. Its altitude goes from 600 to 1,000 meters over sea level.
The Sierra del Escudo de Cabuérniga runs parallel to the coast, separated 15–20 km from it, which is why it has traditionally been considered the border between La Marina (The Coast) and La Montaña (The Mountain). The range is broken in several places by gorges eroded by the rivers which flow perpendicularly from the Cantabrian Mountains into the sea. Its continuity is very well marked in the western zone of Cantabria, while to the east, its orography starts to dilute, although the appearance of great faults mark its East-West route.
787.02 hectares of the central strip of the range, near Carmona, are catalogued as a Site of Community Importance.