The Oat Hill Mine Trail is more of a road than a trail. A former stage coach route, this route leads to a former mining camp in Calistoga, California. While it’s a bit of a haul from the heart of the bay area, the views and the rocky tread make it worth checking out at least once. While most of the Mine route is double track, it is reminiscent of Moab style double track, making for an interesting trail experience.
Because much of the trail surface is made of rock, it makes for a good destination in the rainy season, although its a bit of a trek to get out there.
As an out and back, this ride is about 10miles long. There are additional options on routes though, including a pretty epic, mostly down hill shuttle option which we did once years ago. Don’t ask me how to get there though, as we were guided by a local. Plenty has been written on this trail, check out a solid and thorough review on Ogrehut.com.