From interstate 80 in Truckee, take Highway 89S and drive to Tahoe City. Continue south on Highway 89 from Tahoe City for another 4.2 miles to Caspian Picnic Area. Turn west on Blackwood Canyon Road. The road follows Blackwood creek for 2.3 miles, crosses the creek and then climbs 4.8 miles to Barker Pass.
Pavement ends at the summit.
The Powderhorn trailhead is 2.3 miles down the road from where the pavement ends. From Barker Pass Road, the trail ascends through private land up to a broad saddle where it ties in with a logging road. Follow the road .2 miles to where the trail leaves the road. From the boundary, the trail descends through fields of wildflowers following the Powderhorn creek drainage. Volcanic rock of many sizes and textures can also be observed.