Close enough Old Oat Hill Mine Road, from Calistoga to Middletown or Pope Valley.
Had an old mercury mine there too.
Closed because Nature Conservancy bought a very, tiny piece of property, which happened to contain the trail head, put up a gate, and closed the best and closest wheeling to all of the bay Area.... and near by towns, especially Napa.
I spent a great many days, and a few nights there.
It is too bad, we weren't aware much of closures, or didn't try to buy that small piece of property.
That event was one of the major wake-up calls that told me we HAD to get involved in land use issues or lose a LOT... and 30+ years later, look how true that is.
Ken