Alto de San Isidro
Spain, europe
27 km
1,523 m
hard
Year-round
# Alto de San Isidro: A Spanish Mountain Pass Worth the Drive
Perched at 1,523 meters (4,996 feet) on the border between Asturias and Castile and Leon in northern Spain, Alto de San Isidro—also called Puerto de San Isidro—is a stunning mountain pass nestled within the Redes Natural Park. This is one of those climbs that'll get your heart pumping in the best way possible.
The good news? The road is fully asphalted and genuinely well-maintained, thanks to it being the main route up to the local ski slopes. It's also plenty wide, making it feel relatively safe as you wind your way up. The climb does get serious though, with some sections hitting 11.4% gradient, so don't expect a casual cruise.
You've got two solid options for tackling this pass. Coming from Cabañaquinta on the AS-253 road gives you the longer but more gradual approach—27km of climbing with 1,111 meters of elevation gain and an average gradient of 4.1%. If you're coming from Puebla de Lillo via LE-331, you're looking at a shorter 14.7km haul with 433 meters of elevation gain and a mellower 2.5% average gradient, though even this route has some spicy 8.7% sections.
One heads-up: winters here get seriously cold, so come prepared if you're tackling this in the colder months. The silver lining is that the pass typically stays open year-round to keep ski access flowing. Pro cyclists have conquered this beauty too—it's been featured in the Spanish Vuelta.
Ready to give it a go?
Where is it?
Alto de San Isidro is located in Spain (europe). Coordinates: 40.9502, -4.0238
Road Details
- Country
- Spain
- Continent
- europe
- Length
- 27 km
- Max Elevation
- 1,523 m
- Difficulty
- hard
- Coordinates
- 40.9502, -4.0238
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