The Medio Maratón Bajo Pas is a 21 km half marathon held in Oruña de Piélagos, Cantabria. It takes place in September and is organized by the Piélagos town council, with the municipality acting as the local athletics center for the event.
The public race listing states the distance as 21 km but lacks a detailed route description. Notably, for a local half marathon, its scale is significant: the 38th edition reached its 500-runner capacity, and the event boasts a long history with 38 editions completed.