34°20′33″N 118°00′36″W / 34.3425°N 118.01°W Horse Flats is a region of the San Gabriel Mountains in the Angeles National Forest north of Los Angeles. It is known for its US Forest Service campground (open April 1-November 15) and for the excellent granite bouldering near the campground. It is off California State Route 2. The elevation is 5,800 ft (1,800 m). Closed in the winter months.[1] In the campground is Mount Hillyer Trail, which connects to the Silver Moccasin Trail. [2][3]
In the nineteenth century, the area was used by Tiburcio Vásquez and his gang as a hideout and corral for their stolen livestock[4]