Outdoor recreation represents one of the greatest gifts of the canyons and thousands of people each year enjoy hiking, biking, horseback riding, and driving through its mountains. Protecting one of the last large blocks of natural habitat in Southern California, the canyons offer broad washes bordered by sycamore and willow riparian habitats, oak woodland, native and non-native annual grasslands and coastal sage scrub. The largest tributary of Orange County's major river, the Santa Ana, originates in the canyons at Santiago Peak and provides critical habitat for many birds and mammals. In partnership with the Irvine Ranch Conservancy, OC Parks offers a number of hikes, trail rides, biking events and interpretative walks in the canyons. The two activity areas are Limestone Canyon, which is close to the bat bridge on Santiago Canyon Road, and Black Star Canyon. ALL ACTIVITIES ARE FREE!!!!