During the 19th century this was a busy road, the trail was used to hauls supplies and ore to the mine camp at the top of the hill. There was also a stagecoach route which followed along this trail. When you are riding up the Oat Hill Mine Trail it is very easy to visualize someone struggling up this road in a horse drawn wagon or stagecoach. The path would be difficult, as the trail gets very narrow and washed out in places. Higher up the trail there are ruts carved by the wagon into solid rock of the trail.
The mine was closed eventually and the stagecoach made obsolete by trains and later cars. The trail fell into disuse until adventurous motorists with 4 wheel drive trucks and jeeps discovered the trail. For the 4-wheelers this place was a great challenge. The trail was so narrow at points that would scrape the paint off of the side of the truck to squeeze past the narrow spots. Eventually in the late 80's this path was closed to 4 wheel drive vehicles because of fatalities on this trail.
So now mountain bikers and hikes have inherited this trail with it's rich heritage and adventurous past. The trail is receives little or no regular maintenance so it is a very rough and during the winter entire sections of the trail essentially become creek beds. The Oat Hill Mine Trail is 9 miles out and back (with options for more miles at the top) and has a lot of climbing. The trail is very technical in parts and would be exceptionally difficult for a beginning rider.
The trail is easy to find, it's east of Calistoga at the intersection of Silverado trail and highway 29. I suggest that if you are coming from the south that you tail Silverado Trail road north from Napa rather that taking Highway 29. There didn't seem to be much traffic on Silverado trail and it bypasses most of the small towns with stop lights and drunks stumbling out of the wineries.
The trail head is on the right hand side of the road at the intersection. You can park at the trail head or on the left under some nice shade trees.
2002 Oat Hill Ride - Pictures and a ride report from when I rode here in 2002.