Summit Trail to Rock City and Sentinel Rock is a 4.1 mile moderately trafficked out and back trail located near Diablo, California that features beautiful wild flowers and is rated as moderate. The trail offers a number of activity options and is accessible year-round.
The hike starts by the south entrance to Mt. Diablo State Park and follows the Summit trail past the Live Oak camping area. From there it's just a short walk to the Rock City area in the park which is marked by a wide variety of rock structures including the so-called 'wind caves'. These were actually formed through erosion by flowing water creating large hollowed-out areas in the sandstone. A prominent feature is Sentinel Rock that stands well above the surroundings and provides a panoramic view from its summit. There are steps carved into the rock and iron railings at key points for safety when climbing to the top.
Yes, parking can be a little challenging since they put in rocks on small shoulder to stop people parking there. Park a little up the street or before.
Dogs are actually not allowed in Mt Diablo State Park - even leash.
Overall great hike, with mix of easy fire trail, good inclines, lower tree canopy for shade, and a ton of fun on rocks in Rock City. Be sure to climb up to top of Sentinel Rock! Can be a little nerve-racking, but you won't be disappointed.
This is typically a busy trail on weekends and need to watch for mountain bikes.
I would have given 5 stars, but agree parking is challenging. Looking at map, may be better to park in one of neighborhoods on left towards Stone Valley Rd.