Turnbull Canyon is a popular LA area mountain bike spot located in Whittier. It’s also pretty popular with hikers, so be sure to keep your eyes open, but the mountain biking contingent here is strong!
There’s a combination of doubletrack/fireroads and singletrack out here. From the Beverly lot (the GPS location given for the trailhead), start grinding up the fireroad to the top of the ridge. Once on top, there are a number of options for some awesome descending down the front side, or you could hit up 7th street and descend down the opposite side of the ridge, but be prepared for the ride back up!
On the opposite side of Turnbull Canyon Road you’ll find some fireroads and some great singletrack—specifically, the Worsham Canyon Trail is an absolute joy to ride!
While you won’t be on singletrack the entire time you’re here, Turnbull is a great place to get in as much as 15-20 miles of legit mountain biking!