The activities below are offered by a variety of organizations and their dedicated volunteers. All programs are FREE unless noted below. Programs led by IRC-Certified Volunteers require pre-registration, which closes at 4 p.m. on the day prior to the event. No walk-up registrations will be permitted for these events. For policies of other organizations, please use the sign-up information provided. For mobility device policies click here.
Note: Minors must be accompanied by a parent or guardian for these events. For programs requiring online registration, each adult and child must be registered. |
Need help? For the fastest answers, look for organization-specific contact information in each event listing (click More Information for full listing). If no contact information is listed, email info@irconservancy.org for assistance.
Click here to learn more about IRC-Certified Volunteers. • Click here to learn more about the Difficulty Ratings.
Sunday, April 16, 2023
Earthcache Hike to East Sinks

Come and hike with us to the East Sinks in Limestone Canyon, location of the Earthcache site — a special place people can visit to learn about unique aspects of the Earth — listed on www.geocaching.com. The cache is titled “The Sinks- Irvine Ranch Wildlands, GC1ZB6V.” This hike is open to existing geocachers, those curious about geocaching and non-geocachers alike. There will be as much time as needed spent at The Sinks so all geocachers can record their data and make their observations to confidently log their visit to this cache site.
Reviewing the 1-through-5 Difficulty Ratings will help you evaluate your readiness to participate in this level-4 activity on the land.
Tuesday, April 25, 2023
Twilight Hike in Limestone Canyon

Limestone Canyon is a treasure waiting to be discovered. Join us for an evening, moderately-paced, 10-mile hike. The hike may include a few short rest stops along the way and will be a great introduction to fitness, fitness-style hikes as well as OCParks’ magnificent Irvine Ranch Open Space. Views of Limestone Canyon, and the surrounding wilderness, from Limestone Ridge along with a visit to the East Sinks will be the highlight of our tour.
Please bring a minimum of 70 oz. water. Come prepared with a pack, sturdy closed-toed hiking shoes or boots, sunscreen, first aid, and all other supplies to keep you safe and healthy on the trail for this fitness-paced (3-3.5 mph with very few stops) hike in a wilderness area. Each participant must carry his or her own pack and water. Under-prepared participants may be denied access to this program.
Reviewing the 1-through-5 Difficulty Ratings will help you evaluate your readiness to participate in this level 4 activity on the land. Please visit our FAQ page for answers to activity specific questions you may have prior to registering.
Saturday, May 13, 2023
Agua Chinon and the Sinks Exploration

Please note: Preregistration is required due to limited parking capacity.
Start your weekend off by exploring the Agua Chinon wash and the Sinks through this self-guided opportunity. Designated trails will be open for self-guided trail use in OC Parks’ Irvine Ranch Open Space. Trail routes vary in distance and level of difficulty with choices ranging from easy one-hour walks to a strenuous 9.5-mile trek. Whether traveling by feet or on two wheels, this exploration day is a treasure waiting to be discovered by hikers and mountain bikers alike. Visitors to the Open Space during this activity are able to hike or bike to the West and East Sinks viewing areas.
Please review our Trail Tips page and FAQ page to prepare for this challenging hiking and biking opportunity.
Monday, May 15, 2023
Twilight Hike in Limestone Canyon

Limestone Canyon is a treasure waiting to be discovered. Join us for an evening, moderately-paced, 10-mile hike. The hike may include a few short rest stops along the way and will be a great introduction to fitness, fitness-style hikes as well as OCParks’ magnificent Irvine Ranch Open Space. Views of Limestone Canyon, and the surrounding wilderness, from Limestone Ridge along with a visit to the East Sinks will be the highlight of our tour.
Please bring a minimum of 70 oz. water. Come prepared with a pack, sturdy closed-toed hiking shoes or boots, sunscreen, first aid, and all other supplies to keep you safe and healthy on the trail for this fitness-paced (3-3.5 mph with very few stops) hike in a wilderness area. Each participant must carry his or her own pack and water. Under-prepared participants may be denied access to this program.
Reviewing the 1-through-5 Difficulty Ratings will help you evaluate your readiness to participate in this level 4 activity on the land. Please visit our FAQ page for answers to activity specific questions you may have prior to registering.
Sunday, May 21, 2023
Photo Journey Limestone Canyon: The Sinks, Loma Ridge Backcountry and Sunset

Join us in the back-country wilderness for a journey filled with beautiful sights that are photographic and artistic sketching opportunities. Our journey begins in the afternoon. We will be deep in a secluded canyon, where time is measured in centuries, even millennia, in the sandstone cliffs of this ancient place called Limestone Canyon.
You will board a 4-wheel drive vehicle for a 13-mile tour of the canyon and hills surrounding it. We will stop frequently for 15-30 minutes to admire the views, take photos, sketch landscapes, and answer questions. Stops will include short walks with views of The Sinks, a trip up Cactus and Markel Spur, with optional, single track, one-mile hike into Box Springs or a 1.5 mile Markel Spur to East Sinks loop hike. Both the Box Springs and Markel Spur hikes provide the visitor a true back-country experience. An alternative, but similar, hiking trail may be used.
Reviewing the 1-through-5 Difficulty Ratings will help you evaluate your readiness to participate in this level-2 activity on the land. Please visit our FAQ page for answers to activity specific questions you may have prior to registering.
Tuesday, June 13, 2023
Limestone Canyon Distance Hike: Panoramic Sinks View from the Water Tank

Explore beautiful Limestone Canyon on this challenging distance hike to the “water tank” beyond the East Sinks viewing area. This distance hike rewards hikers with panoramic unobstructed views of The Sinks, an ancient and dramatic formation of exposed sandstone cliffs. Limestone Canyon is one of the most pristine wilderness areas in the county. In addition to providing sweeping views, the trail passes through coastal sage scrub, grasslands, and oak woodlands. This hike moves between 3 and 3.5 mph with multiple sustained climbs.
Reviewing the 1-through-5 Difficulty Ratings will help you evaluate your readiness to participate in this level-5 activity on the land.