Oursan trail is a 13.5 mile lightly trafficked loop trail located near Orinda, CA that features a lake. The trail is rated as moderate and primarily used for hiking and horses. Dogs are also able to use this trail but must be kept on leash.
dogs on leash
Oursan Trail circumnavigates Briones Reservoir. A trail permit is required, and you must register at the trailhead. The permit is valid for a year and may be used at other EB Watershed reservoirs. Purchase permits online at: http://www.ebmud.com/recreation/east-bay-trails A combo trail that, counter-clockwise from the Bear Creek Road Staging Area, starts as a defunct ranch road rolling up and down moderate hills. After crossing the dam (about 2/3 of the way around), the road becomes a trail and winds through the shade of dramatic oak woodlands.
13.5? Make that 16.5miles with 1800' of elevation gain according to Strava. This is a serious hike. Took us 5hrs to complete.
Overall I would not recommend at this time. The trails on the north side are completely beat up by a combo of the rain and cow tracks. It's brutal on the feet and ankles, not to mention, not very much fun.
This would be a 4 star hike if it wasn't for the beat up trail.
A long hike -- 1/2 marathon! Don't forget to get your trail permit. Fun to walk around a lake. Saw hawks, Canada geese, turkeys, crows, swallows. Early spring day was sunny and warm. Most of the hike is pretty open, so it's probably pretty warm in the summer. There's a nice section in a beautiful, cool grove of grizzled oaks. Some benches in this section for quiet contemplation.