» Official Trail Map for Rancho San Antonio Park: High quality map showing various trail sections, including trails to Black Mountain.
» Official Trail Map: Pretty good map showing various trails.
» Redwoodhikes Trail Map:
Great map showing many parks like Purisima Creek, Huddart, Wunderlich, El Corte De Madera, Foothills, Hidden Villa and Rancho San Antonio. Trail maps for individual parks are available online for free. However, the RedwoodHikes map shows the big picture and is helpful for planning hikes that go through multiple parks.
To Black Mountain (6.1 miles): From the parking lot next to Hidden Villa Gate, follow the semi-paved road leading towards the farm (0.3 miles). Upon reaching the hostel, turn left onto an unnamed trail (0.6 miles). Turn left onto Toyon Trail (0.5 miles) to reach an intersection with Bypass Trail and Creek Trail. This is the most beautiful spot in the entire route. It lies at the confluence of multiple creeks (see trail map). It is shaded, with bridges and even some picnic tables. Continue along Creek Trail (1.0 miles) → Ewing Trail (0.7 miles) → right on Black Mountain Trail (3.0 miles) to reach Black Mountain.
To Hidden Villa Parking Lot (5.2 miles): From Black Mountain, retrace your steps along Black Mountain Trail (3.0 miles) to reach the intersection with Ewing Trail. Continue along Black Mountain Trail (0.3 miles) → left on Hostel Trail (1.0 miles) → right on unnamed trail (0.6 miles) → right on semi-paved road leading to the parking lot near Hidden Villa Gate (0.3 miles).
Notes: The last one mile along Black Mountain Trail is pretty steep, among the steepest trails in the bay area.