Single track mountain biking trails west of Rapid City. Depending on the route, the trail is 7 to 8 miles long.
To get there take Hwy 44 West (Rimrock) about 5.6 miles from Canyon Lake Park. The Quarry is on the right hand side. Watch for a forest road with an open gate that you can see from the highway. When the gate is open you can drive down to the bottom to park (keep to the left when the road forks).