The Mt. Hillyer Trail from Horse Flats Campground horse trail is a 3.2 mile Out & back trail that wanders through the San Gabriel Mountains National Monument and . This trail is accessible in Spring, Summer, Fall, Winter.
The Mt. Hillyer Trail from Horse Flats Campground horse trail is a 3.2 mile Out & back trail that wanders through the San Gabriel Mountains National Monument and . This trail is accessible in Spring, Summer, Fall, Winter.