Skyline 50k Endurance Run
Castro Valley, United States • 2 Aug 2026
Skyline 50k Endurance Run
Skyline 50k Endurance Run takes place on Sunday, August 2, 2026 in Castro Valley, California, with the course starting and finishing at Lake Chabot Marina. The route is a large loop through East Bay Regional Parks that reaches Skyline Gate and includes substantial climbing on singletrack and fire roads.
Distances offered:
- 50K
- 21K
The event is described as one of the oldest continuously running 50k races in the United States and has been selected as an OG Ultra by Ultrarunning Magazine. Organizers provide digital race information in advance and an optional bib pickup at Sports Basement Berkeley. GPX files and athlete guides for both the 50k and half marathon are available.
Volunteer support is prominent along the course, with multiple local groups staffing aid stations and assisting at intersections. Every finisher receives a race shirt, special Skyline socks, and a finisher's medal. Overall winners and age group leaders are recognized with awards three deep.
Skyline 50k is included in the P-USATF Grand Prix and both distances are listed as UTMB Index races. The 2026 edition is dedicated to the memory of a former race director. Visit the organization's website for the most recent information.