OC Parks' intermediate ride links Irvine Ranch Open Space with Limestone Canyon Nature Preserve on a demanding docent-led loop. The group starts at the gated Hicks Haul Road / Jeffrey staging area, warms up on the paved Hicks Haul climb, follows Loma Ridge east, drops singletrack toward Box Springs, pauses at The Sinks, then returns via Limestone Ridge, Augustine and Loma Ridge before coasting back to the start. The live registration detail rates the outing level 4: 16 miles with about 2,200 feet of elevation change in three and a half hours. Riders must be at least 18, arrive with their own trail-ready mountain bike and safety supplies, and be prepared for sustained climbing, singletrack descents and natural hazards. Advance online registration is mandatory, no walk-ups are accepted, and the organizer showed 5 of 15 spaces left during October 1 verification. Limestone Canyon is scheduled-access land; exact final directions are released after registration.

OC Parks / Irvine Ranch Open Space

Level-4 intermediate guided ride

Minimum age 18. Riders should be ready for a level-4, 16-mile outing with about 2,200 feet of climbing/descending, sustained paved climbing, steep or technical singletrack, an 8-10 mph average pace, minimal regrouping and expected trailside-repair knowledge.

Upcoming guided community ride; no competition, purse, podium, livestream, results or replay is planned.

Intermediate Mountain Bike Ride from Irvine to Limestone Canyon

Hicks Haul Road Staging Area - Limestone Canyon Nature Preserve

OC Parks' slow-paced Limestone Canyon ride gives experienced beginners a supported step up from fire roads into Orange County singletrack. The docent-led group leaves Augustine Staging Area, rides approximately 11 miles with 1,450 feet of elevation change, descends Dripping Springs singletrack to the East Viewing Platform at The Sinks, then returns on Limestone Ridge with views across Limestone Canyon, Santiago Canyon and the Santa Ana Mountains. Let’s Go Outside rates the outing level 3 and requires riders to be at least 14. Advance account-based registration is mandatory, no walk-ups are accepted, electric or other motorized bikes are prohibited, and the live listing showed 10 of 15 spaces remaining during October 1 verification. Limestone Canyon is scheduled-access preserve land, so riders should use the gated Augustine staging entrance and follow the directions and final instructions sent with registration.

OC Parks / Irvine Ranch Conservancy

Level-3 slow-paced guided ride

Minimum age 14. Riders should already be comfortable on fire roads and ready to develop climbing and singletrack skills over 11 miles and about 1,450 feet of elevation change.

Upcoming noncompetitive guided ride; no purse, podium, livestream, results or replay is planned.

Slow-paced Mountain Bike Ride: Limestone Canyon/East Sinks

Augustine Staging Area - Limestone Canyon Nature Preserve

OC Parks' Limestone and Red Rock Night Ride is a docent-led mountain-bike outing through scheduled-access Limestone Canyon Nature Preserve and Red Rock Wilderness. The group leaves Augustine Staging Area at 5:30 PM, rides about 12 miles with 1,500 feet of climbing on ranch roads and varied singletrack, and returns around 8:00 PM after dark. Let’s Go Outside rates the ride level 4, requires participants to be at least 16, and explicitly says this should not be a rider's first night ride. Riders must be self-sufficient with adequate lights, a jacket, water, spare tubes and tools. Advance account-based registration is mandatory, no walk-ups are accepted, and registration opens October 12 at 8:00 AM; capacity, fee and waitlist details are not public before the opening. Electric mountain bikes and all other motorized recreation vehicles are prohibited. Trail conditions can change the exact route, and final access directions are shared with registered participants.

Level-4 guided night ride

Minimum age 16. Riders must already have night-riding experience, be fit for 12 miles and about 1,500 feet of climbing, and be comfortable on varied singletrack and ranch roads after dark.

Upcoming OC Parks scheduled Limestone Canyon programs Events

Intermediate Mountain Bike Ride from Irvine to Limestone Canyon

Slow-paced Mountain Bike Ride: Limestone Canyon/East Sinks

Limestone and Red Rock Night Ride