Ridge-to-Ridge Challenge

Ridge-to-Ridge Challenge 2026

The Ridge-to-Ridge Challenge is an annual fundraiser supporting Sustainable Contra Costa and its youth program Sustainable Leaders in Action (SLIA). High school and college students collaborate to raise awareness about climate issues and to promote non-political sustainability efforts across Contra Costa County. The event takes place at Shell Ridge Open Space in Walnut Creek on Saturday, May 9, 2026.

All courses start and finish at the Open Space entrance at the south end of Marshall Drive. Participants can choose among multiple course experiences and formats:

• Fossil Hill Scavenger Hunt : ~1.4 miles
• Indian Valley Nature Walk : ~1.4 miles
• Ridge-to-Ridge Challenge Run : 5K / 3.1 miles

The Fossil Hill Scavenger Hunt is a walking loop around Fossil Hill designed for individuals or teams. Participants follow puzzle-style clues to find scavenger points, photograph each location, and return to the finish after locating all points.

The Indian Valley Nature Walk is a relaxed educational walk that includes short talks from local experts on topics such as the geology of Shell Ridge, Indian Creek restoration, the history of Quarry Hill and Fossil Hill, native plants and habitat restoration, and wildlife of the open space.

The Ridge-to-Ridge Challenge Run is a trail run that traverses hills and valleys within the open space over a 5K course. Visit the organization's website for the most recent information.