This is probably the signiture loop trail within the fantastic Whiskeytown National Recreation Area west of Redding. A short dirt road descent is followed by about 3-mile climb that's moderate to steep and crosses one small stream. A sharp left turn (1 mile after the creek) puts you on double track that climbs another 1/2 mile, tops out, crosses another stream and turns into a great singletrack. The descent is a classic mix of rocky double track and singletrack, some of it buffed out and fast.
How to get there:
Take Highway 299 west from Redding, which is in far north-central California. Turn left on JFK Memorial Drive and veer left on Paige Bar road (below the Whiskeytown Lake dam) to the large dirt Peltier Valley parking lot on the left. The trail begins on Peltier Valley road on the opposite side of the parking lot.
There's a steep, technical section prior to the second stream crossing on the top of the climb.