A fantastic loop hike in the Chino Hills. Although it's difficult to imagine te hike will be anything but horrible in the first mile as you walk alongside the 91 freeway. But once you pass under the freeway and into Chino Hills State Park, the views and landscape are fantastic. Take the fire road (Coal Canyon West Trail) up to Picnic Rock, passing through a rich Cypress forest on the way. From Picnic Rock you follow Leonard Road as it meanders up the ridgeline to Sierra Peak. The summit is no more than a gathering of electrical towers, but we were grateful to be able to find a spot behind a wall to enjoy lunch out of the wind. On the way down we took Pipeline Road, at times steep and slippery in the rain. There is really no shade on this trail so I would recommend it on a cool day, or a day like we chose, with sun, wind and rain!