Santiago Oaks Regional Park is located in Orange California. It has some excellent trails for hiking, biking, and horseback riding. The park is located in the heart of Orange County, but it feels surprisingly remote once you get into the canyon and up into the hills. There are several easy trails that follow the creek, and a few that go straight up the mountain. The reward of riding down is worth the effort getting up. The trails are wide, fast, and well maintained. This is easily one of the best areas in Orange County for mountain biking. Here is a map of the trails.
Mountain Biking in Santiago Oaks Regional Park from john fakor on Vimeo.