Redtail Ridge

Castro Valley, United States • 21 Feb 2026

Redtail Ridge at Lake Chabot Regional Park in Castro Valley, CA offers multiple distances: 5K, 10K, Half Marathon, 30K, and 50K. The course unfolds on a mix of moderately technical dirt trails and non-technical fire roads, with some paved sections, and features rolling hills that reward pacing and technique. Elevation gains range from about 110 ft for the 5K up to 3,800 ft for the 50K. The event emphasizes a cupless format with supportive aid stations, a well-staffed finish area, and race-day shirts. Capacity is 500 runners; dogs on leash are allowed; volunteers and spectators welcome in this scenic Bay Area trail run. Visit the organization's website for the most recent information.

Race information

50 km
3800 m+
50k
30 km
2300 m+
30k
21 km
1800 m+
Half Marathon
10 km
650 m+
10k
5 km
110 m+
Visit the organization's website for the most recent information.
Trail runs nearby

The Mt. Umunhum Marathon, Race to the Top and Down, is a challenging trail running event held in Almaden Quicksilver County Park, San Jose, California. This marathon features a rugged course that begins at the Hacienda Entrance and ascends to the summit of Mt.Umunhum, one of the prominent peaks in t..

Rocky Ridge is a trail race set in the Las Trampas Wilderness near San Ramon, California. The event offers a half marathon, a 10K, and a 5K through rugged hills and scenic vistas. The course is demanding and not beginner-friendly, rewarding perseverance with trails and views few runners will see, fo..

Pacifica Summit Run, staged at San Pedro Valley State Park in Pacifica, California, features 10K and half-marathon trail races hosted by Urban Coyote Racing. Runners enjoy postcard views of the Pacific Ocean coastline and plenty of switchbacks as they ascend the summit on the upper San Francisco Pen..

Dick Collins Firetrails is the 42nd annual trail event presented by Scena Performance at Lake Chabot Regional Park (17936 Lake Chabot Rd). The event comprises multiple trail races on East Bay regional trails, including sections on Dinosaur Ridge, the Garin-Chabot Trail, Skyline Gate, Reinhardt Redw..

UTMB Index

Spartan Trail San Jose Challenge takes place at Sanborn County Park in the eastern Santa Cruz Mountains near Saratoga, California, with the race site at West Valley College Parking Lot 5. The event offers three trail distances: 50K, 21K, and 10K. Runners tackle well‑groomed yet steep and difficult t..

The Trailblazer Race in Mountain View, CA, is an annual family-friendly event featuring 10K and 5K runs, plus a 3-mile walk along the scenic Stevens Creek Trail and Shoreline Park. The courses are fast, flat, and stroller-friendly, offering beautiful views of wildlife, salt ponds, and surrounding mo..