A former trade route of the Republic of Venice, Passo San Marco links Val Brembana to Valtellina via a long, demanding climb, rated hors catégorie when it featured in the 2007 Giro d’Italia.
A long hors-catégorie climb
From Olmo al Brembo, it’s 19.2 km for 1,436 m of elevation gain, averaging 7.5%, with occasional ramps beyond 15%. The summit sits at 1,992 m, deep in the Orobie Alps.
A road with Venetian history
Built in the late 16th century to bypass Milanese territory, the road still preserves the Ca’ San Marco near the summit, a rest-house from that era still standing — witness to more than four centuries of traffic between the two valleys.
Getting the ride right
The climb’s length and its sustained sections beyond 15% call for careful pacing from the bottom of the ascent, with a wide-range cassette making the steepest ramps far more manageable.
When to go
June to September — the pass’s altitude makes the climb impractical outside this window, as snow can linger late into spring.
Good to know
Morbegno on the Valtellina side and Olmo al Brembo on the Val Brembana side offer two very different approaches to the pass, the latter noticeably longer and gentler.
