Desfiladero de Los Beyos, Limestone defile between Asturias and León Province, Spain

Desfiladero de Los Beyos is a limestone gorge carved by the Sella River along the border between Asturias and León Province in Spain. The river and a narrow road run side by side through the passage, hemmed in by tall vertical rock walls on both sides.

A footpath through the gorge was opened in 1665, funded by Pedro Díaz de Oseja to connect isolated settlements on both sides. Local residents maintained that trail for centuries before a paved road was eventually built along the same route.

The name comes from the local word beyu, meaning a narrow gorge or defile. Until the late 19th-century road, the Camino del Beyo was the only route through, used by people and livestock; its wooden bridges were described in 1829 as very tall beams spanning the gap. The gorge still divides three municipalities: Sajambre in León, and Ponga and Amieva in Asturias.

The road through the gorge is narrow and winding, so drivers should go slowly and stay alert for oncoming vehicles at blind bends. Approaching from the north via Amieva or from the south via Oseja de Sajambre are the two main options.

The gorge's name comes from beyu, the local word for a narrow pass or ravine. In the first stretch, between Cobarcil and the Angoyo bridge, the rock formations El Frailón and Les Monxines stand out; locals also call them pica la Plana and los Cuatro Picos. Further north, near Vidosa, the Aguasalió waterfall drops into the gorge.