Hanna Flat Trail is a hiking and biking trail in San Bernardino County, California. It is within San Bernardino National Forest. It is 3.7 miles long and begins at 7,078 feet altitude. Traveling the entire trail is 6.1 miles with a total elevation gain of 1,305 feet. The Hanna Flat Campground camp site is near the trailhead. Along the trail there is a viewpoint.