Notes: Nortonville Trail is a wide fire road that takes you up and down a hill as you travel west from Somersville Rd trail head. Coal Canyon Trail is a nice trail that climbs quickly out of a canyon, meandering through a forest. Black Diamond Way is a paved road for about half a mile with lush green trees and meadows on both sides in spring. Black Diamond Trail is a wide fire road. Manhattan Canyon Trail and Chaparral Loop Trail take you through a forest. Some sections of these trails are steep.
From I-680 North, take CA-242 North and drive for 3.2 miles. Continue along CA-4 East and drive for 11.6 miles. Take exit 26B for Auto Center Drive and turn right onto Auto Center Drive / Somersville Rd. Within 0.1 miles, make a U-Turn and follow Somersville Rd for 3.7 miles. There are two parking lots on Somersville Rd for Black Diamond. The trailhead is at the second parking lot, deeper into the park.
Parking Fees: $5 per vehicle when entry kiosk was manned, free otherwise. (last visited: April 2011)