All of us who enjoy walking in Mount Diablo State Park have our own favorite destination, perhaps a secret spot which we visit now and then, where we find peace of mind and nature at its best. The topographic complexity of Mount Diablo shelters quite an array of such spots—possibly a hidden cascade on the Falls Trail, a favorite formation on China Wall, or the perennial display of JohnnyJump-Ups on the Bruce Lee Road. My own favorite secret spot is “The Amphitheater”.

“The Amphitheater” is a unique phenomenon in Mount Diablo State Park. It is a large bowl formed by the vertical cliffs of Highland Ridge, with sides of enveloping sandstone strata tilted and eroded into picturesque outcrops, not unlike those in Rock City. The bowl bottom is a level area of deep soil supporting a growth of lush grasses and magnificent, centuries-old oak trees, scattered like isolated giant sentinels across the green sward. It is a pastoral scene of unmatched beauty, and on a quiet sunny day you can imagine ghostly images of dancing nymphs in the mottled shade of the huge overhanging limbs, a vision from Greek mythology. The magic of this secret spot is enhanced by its location, in the southeastern-most part of the Park bordering Morgan Territory Regional Preserve, an area much less often visited than the main peak. Chances are you will have “The Amphitheater” all to yourself.

A relatively easy way to reach “The Amphitheater” is from the Red Corral trailhead. Red Corral is on Morgan Territory Road, just one half mile beyond the twin narrow bridges, in the direction of Morgan Territory Regional Preserve, or south. You cannot miss the corral on your left, as it is indeed painted red. There is very limited parking at the edge of the road; be sure not to block access to the two gates across the road from the corral.

Start your walk at the left of the two gates, and follow the road straight ahead; posted “Morgan Creek Road”. The route takes you upward through a mature stream-side deciduous forest. Soon you penetrate a more open oak savanna where the road veers to the left. Here be on the lookout for a single-track trail on your right, Jeremiah Creek Trail. It is a delightful path that wends its way at the side of Jeremiah Creek, through an open forest typical of our coastal ranges. The gently rising route ends in a saddle of Highland Ridge, on the Old Finley Road.

Take a left on Old Finley Road, and after a few steps, at another junction, follow the road as it veers off to the right and downhill. You will be treated to fine views of the Jackass Canyon wilderness below you and imposing Oyster Point beyond. After just a few minutes of easy walking, you will reach the first single-track trail on your left, the beginning of the posted Amphitheatre Trail. A short jaunt will deposit you in the middle of “The Amphitheater”, such a welcoming environment, to let you rest from your exertions so far. Find a sheltered spot for a picnic lunch, and afterward do a bit of exploring to discover any number of surprises. You might even scramble up one of the gentler sandstone formations for a bird’s-eye overlook. Photographic opportunities abound—if you find those nymphs, bring me a picture! The easiest way to return to your car is by retracing your steps. Should you prefer to see new things on the way back, however, why not complete a loop that will not take you all that much longer? Continue on the Amphitheatre Trail to its end at Crestview Road. This trail meanders below Highland Ridge, and its final climb to meet Crestview Road is quite steep, but not long. At Crestview Road turn left. Notice the spectacular views of Mount Diablo in profile and the distant delta region. Shortly you will reach the Highland Ridge Trail. Here make a sharp left and continue until you reach the posted “Morgan Creek Road” on your right, which you descend back to Red Corral. 

The loop is less than five miles, and your total climb is just under 1,000 feet. Figure on two-and-one-half hours of walking plus an hour in “The Amphitheater”.