This is a route straight up a few rolling buttresses on the southwest side of Big Rock Ridge directly from the pass (unnamed) with the big rock for which the ridge is named. There is an excellent trail to the top from the pass that winds along following the contours then switchbacking up the southwest slopes to the top. This direct way follows the main trail only a short distance before going off trail and taking the shortest steepest route to the top cutting the distance to the summit in half. Then it leisurely takes the trail back to enjoy the fine views along the way.
Descending the trail at sunset
From Hwy. 101 north of San Rafael take the Lucas Valley Road exit west 5.5 miles through the valley and up to the pass with the big rock on the right. There is road side parking on the left.
Looking down the direct route
Ascent route: Take the trail going to Big Rock Ridge down to the right of the big rock. (650' el.) Follow the trail .4 mile. Cut off to the left up through the grassy slope and on up to where it meets the trail again in about another .4 mile. (940'el.) Cross the trail and continue straight up the slope on the right side of the old barbed wire fence. Take this steep section up through the grass about .6 miles to where it meets the trail at the top of the ridge once again. (1,800' el.) Follow the fireroad/trail to the right another half mile to the summit towers at 1,887'. Approximately 2 miles.
Take note: Be sure to take into account foxtails getting in your foot garmets in the grass in early summer. You can ruin a pair of socks quickly traipsing though the stuff when it's high and dry.
Descent route: Simply follow the trail back down along the ridge until it switchbacks down the southwest slope and then goes east on the lower slope and
contours back around some ravines and back to the pass at approximately 4 miles.
This route is about 6 miles round trip and 1,240' el. gain.
West from the trail
Good foot support (cross trainers or boots) for the steep sections. A raincoat and or windbreaker in cooler wet weather.. Snacks, lunch and plenty of water on hot summer days. Sunscreen.
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