“A steep climb on a rarely used trail to some great views.
— Matt Freeman
Perhaps during fire season.
This trailhead is located at the Griswold Hills Recreation Access on New Idria Road where there is a BLM vault toilet, picnic table, and shade shelter.
Unfortunately, this site is commonly used for target practice, so there are many signs of bullet shells and destroyed targets.
Go through the metal pedestrian gate, cross over the drainage ditch and find the fiberglass BLM trail marker. The trail begins with a series of switchbacks on a narrow trail. You'll quickly leave the litter of cow dung, bullet casings, and discarded targets.
The vegetation slowly changes from grass and sage to widely dispersed juniper. The higher areas of the trail are used more by critters than humans. In addition, there is a pronounced absence of cow dung, but its replaced with small critter scat and evidence of small game trails crossing the infrequently used singletrack. It appears BLM does NOT maintain this trail. In addition, the grade standards are more of a... straight up the hill... rather using switchbacks in the upper sections.
Bikes are permitted, although most of the way up is more hike-a-bike. Perhaps this is a better hiking or running trail. There are great views of the surrounding mountains, the Panoche Valley, the massive solar farm being constructed, and to the east the San Joaquin Valley.
Finally, the last 1,000 feet looks overwhelming for biking. Either ditch the bike and finish by hiking, or make the final push and be rewarded with a much easier on the ridge ride as the trail meanders up to the top. The top ridge appears to have been dozed many decades ago, so the riding is easier and the options for going beyond the top expand.
At the top, find a glass jar hidden under a pile of rocks with a pencil and paper to record your arrival. Lower your seat and point down for a slow descent, some steep enough to rest your stomach on your bike seat. This trail is one of the few (only?) public access points to this public-use BLM land.