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.

Do you want to explore the Sinks, a geological rock formation that has got its reputation as “Orange County’s miniature Grand Canyon”? Come out and join us on a hike from the Portola staging area to the West Sinks in OC Parks’ Limestone Canyon. Distance is about 6 miles, with some sustained climbing in one section. Participants must wear sturdy, closed-toe hiking shoes. Remember to pack plenty of water, sunscreen, a hat, and all other necessary equipment to keep you safe on the trail. This activity originates in the City of Irvine (Portola Staging Area) and travels into OC Parks’ Irvine Ranch Open Space.

We start our ride through OC Parks’ Irvine Ranch Open Space on the paved Hicks Haul Road, the extension of Jeffrey Rd north of Portola Pkwy. As we warm up on the climb to the top of the road, we enjoy increasingly beautiful views over Irvine. We then follow Loma Ridge to the East, with fantastic vistas of Orange County, the surrounding wildlands, and even Catalina Island on clear days. From Loma Ridge, we descend on a single track to Box Springs which provides year-round water for wildlife like deer.

After the springs, we continue to the Sinks, Orange County’s own “Grand Canyon,” where we enjoy our snacks during a short break. On our way back, we ride along Limestone Ridge, a fun singletrack that leads us towards the Augustine Staging area, enjoying views of Saddleback and Santiago Canyon. From there we will climb back up to Loma Ridge, and then coast back down on the paved Hicks Haul Road to our starting point. Motorized recreation vehicles of any class or type are not permitted for use in the Nature Preserve.

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.

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.

Join us on a slow-paced hike along the back-country ridges and valleys of Agua Chinon Canyon, part of OC Parks’ Irvine Ranch Open Space. We’ll travel on rough old ranch roads passing by woodlands of majestic oak trees and expanses of Coastal Sage Scrub and enjoy wonderful vistas. Total round-trip distance is 6 miles with an elevation gain of 1000 feet at an average moving rate of 2.0-2.5 miles per hour. Some of the hills are strenuous and we will take breaks as needed. Participants should be in good hiking condition and have previously completed a similar distance hike.

Come along with us on this morning hike through beautiful Limestone Canyon Nature Preserve, part of OC Parks’ Irvine Ranch Open Space. You’ll be rewarded with a spectacular view of The Sinks as well as sweeping views of Orange County and the Santa Ana Mountains. This hike involves steep climbs and descents on both double and single-track trails.

Enjoy the relaxation of riding in the wilderness on empty trails. Join us on this docent-led mountain bike ride through Limestone Canyon, part of OCParks’ Irvine Ranch Open Space. We will visit Dripping Springs which is a fern covered, year-round source of water for the local wildlife. The ride will also stop at the west viewing deck for the Sinks. This is a slow-paced ride designed for the beginner that has experience riding fire roads such as Limestone Canyon or Telegraph Canyon but wants to develop their climbing and riding abilities. The ride can also be enjoyed by more advanced riders looking for a relaxed ride in a beautiful setting.

For families and children ages 12 and up who would like to join IRC-certified volunteers in OC Parks’ Irvine Ranch Open Space on a longer, slow-paced, family-oriented ride through sycamores, oaks, and habitat native to California. The route takes us to The Sinks, Orange County’s own “Grand Canyon.” Along the way, we will stop and talk about the local habitat, and hope to see some of our local native animals and raptors. The ride is an 8-9 miles with 400-800 feet of elevation gain that may require hike-a‐bike for some riders. Motorized recreation vehicles of any class or type are not permitted for recreational use.

Join us for a scenic, and challenging distance hike in the beautiful Limestone Canyon Nature Preserve, part of OC Parks’ Irvine Ranch Open Space. This hike is for physically fit hikers who enjoy the challenge of multiple steep climbs and descents. This 10–13 mile hike offers sweeping views of Orange County and the Santa Ana Mountains as well as possible wildlife sightings. This hike may include a visit to The Sinks and/or Dripping Springs.

Join us on an equestrian ride up Agua Chinon Canyon in OC Parks’ Irvine Ranch Open Space. We will make our way to see the wonders of the Sinks, Orange County’s mini Grand Canyon and take in the beauty around us at the Sinks Viewing Deck. Then we will finish our ride back to the staging area.

Come start your week with us on our Super Treks in the Landmarks. Join us as we explore Limestone Canyon, part of OC Parks’ Irvine Ranch Open Space. We will hike across East Loma and enjoy beautiful views of the surrounding hills, out to the coast, and of Irvine Lake. We will continue to Box Springs and the west side of the Sinks before making our return to the staging area. Please wear hiking shoes/boots and bring water, a trail snack, sunscreen, hat, and any other necessary equipment to keep you safe on the trail. Participants must be able to hike 11 miles with an elevation gain of 1800 feet at an average moving rate of 3 miles per hour.

Please join us as we enhance habitat adjacent to the East viewing area at the Sinks in Limestone Canyon. This area is characterized by beautiful geological formations that resemble a mini–Grand Canyon. Volunteers will travel for approximately 20 minutes in an open-air safari style truck to the project site. The morning will be spent watering native shrubs and rebuilding berms. We will be using small shovels and other tools. No experience necessary.

PRE-REGISTRATION is REQUIRED for this event. 

All participants are required to have, a printed copy or on their phone, the confirmation email to show through the window of their vehicle to drive through the entry gate.

You will need the confirmation email for you and your guests to enter the trail system.

Start your weekend off by exploring numerous opportunities found throughout magnificent Limestone Canyon. 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 strenuous 15-mile cardio treks. Whether traveling by feet or wheels, Wilderness Access Day in Limestone Canyon is a treasure waiting to be discovered by hikers and mountain bikers alike.

Participants will want to plan their day successfully by using Trail Tips to prepare.

PRE-REGISTRATION is REQUIRED for this event. 

All participants are required to have, a printed copy or on their phone, the confirmation email to show through the window of their vehicle to drive through the entry gate.

You will need the confirmation email for you and your guests to enter the trail system.

Come experience Limestone Canyon’s beauty from the back of your horse. Designated trails will be open for self-guided access hiking, biking, and equestrian use during Wilderness Access Day in Limestone Canyon. Equestrian riders who have trail riding experience with a fit and able horse will enjoy the historic ranch roads of days gone by. Take in the awe-inspiring vistas from the mighty ridge tops and drink in the cool canyon shade through the oak grove.

There is limited space for equestrian parking. Riders must also have the ability to transport their horse to the staging area.

We start our ride through OC Parks’ Irvine Ranch Open Space on the paved Hicks Haul Road, the extension of Jeffrey Rd north of Portola Pkwy. As we warm up on the climb to the top of the road, we enjoy increasingly beautiful views over Irvine. We then follow Loma Ridge to the East, with fantastic vistas of Orange County, the surrounding wildlands, and even Catalina Island on clear days. From Loma Ridge, we descend on a single track to Box Springs which provides year-round water for wildlife like deer.

After the springs, we continue to the Sinks, Orange County’s own “Grand Canyon,” where we enjoy our snacks during a short break. On our way back, we ride along Limestone Ridge, a fun singletrack that leads us towards the Augustine Staging area, enjoying views of Saddleback and Santiago Canyon. From there we will climb back up to Loma Ridge, and then coast back down on the paved Hicks Haul Road to our starting point. Motorized recreation vehicles of any class or type are not permitted for use in the Nature Preserve.

Come along with us on this morning hike through beautiful Limestone Canyon Nature Preserve, part of OC Parks’ Irvine Ranch Open Space. You’ll be rewarded with a spectacular view of The Sinks as well as sweeping views of Orange County and the Santa Ana Mountains. This hike involves steep climbs and descents on both double and single-track trails.

Join us on this moderate-paced hike over the ridge and the through beautiful Limestone Canyon Nature Preserve, part of OC Parks’ Irvine Ranch Open Space. We will enjoy short breaks at the East and West Sinks viewing platforms before hiking back through the canyon. We will enjoy a view of wonderful vistas in addition to spectacular view of The Sinks. This hike involves hiking on both double and single-track trails with an elevation gain of 1000.

Come out and join us on a breathtaking hike from the Irvine Open Space Preserve into OC Parks’ Limestone Canyon Nature Preserve. This week’s docent-led hike begins in the Agua Chinon wash, continues to The Sinks, and may include a side trip to Box Springs, a natural year-round source of fresh water.

Maximum distance is just short of 8 miles, with some sustained climbing in one section. Participants must wear sturdy, closed-toe hiking shoes. Remember to pack plenty of water, sunscreen, a hat, and all other necessary equipment to keep you safe on the trail. This activity originates in the City of Irvine and travels into OC Parks’ Irvine Ranch Open Space.

Do you want to explore the Sinks, a geological rock formation that has got its reputation as “Orange County’s miniature Grand Canyon”? Come out and join us on a hike from the Portola staging area to the West Sinks in OC Parks’ Limestone Canyon. Distance is about 6 miles, with some sustained climbing in one section. Participants must wear sturdy, closed-toe hiking shoes. Remember to pack plenty of water, sunscreen, a hat, and all other necessary equipment to keep you safe on the trail. This activity originates in the City of Irvine (Portola Staging Area) and travels into OC Parks’ Irvine Ranch Open Space.