With the loop being either all uphill or all downhill, the Guardian and Annie Bidwell Trail (formerly known as the South Rim) is recommended for advanced riders in great shape.
Guardian Trail is an extremely exposed single-track, featuring cliff edges in some areas and amazing views of the gorge.
Annie Bidwell Trail (South Rim) Trail is extremely rocky and very technical, with several drop-offs of more than 4 feet along a washout. Start down a steep fire road at 10 Mile House Trail, take the left turnoff to ride down Guardian Trail.
When Guardian Trail ends at South Rim Trail, bear right (north) for a steep descent to the Annie Bidwell Trail. Keep right for the Ten Mile House Road and back to where you began.
Key Info
Trail Difficulty: Serious/Technical
Trail Length & Type: 8.6 mile loop, Mountain
Best Used: Accessible year-round but closed during wet weather
Trail Map: MTB Project
Directions
From Chico head east on Hwy 32. Turn left on the turnout across from the 10 Mile House Road. Start at the green gate. If you have passed Altatina Drive you have gone too far.