"-Trailhead: Borrego Trailhead. This trailhead is signed. Reached using Forest Road 306. - Distance (one way) to reach Peak 11821: 12.1 miles, elevation gain of almost 6000 ft. Sierra Mosca is 1.5 miles away. - Trails: Borrego Trail #150 (signed), Sierra Mosca Trail #156 (signed), Agua Sarca Trail. The Borrego Trail gets you to the Sierra Mosca Trail. The Sierra Mosca Trail goes to the summit ridge of Peak 11821 where it meets the Agua Sarca Trail. The Agua Sarca goes near the summit of Peak 11821 and near the summit of Sierra Mosca. Both peaks require leaving the trail to reach the highpoint. Any other trails you see on a map going up/down Sierra Mosca no longer exist. Expect to bushwhack down unless you reverse direction and return the way you came. The bushwhack down off Sierra Mosca to the Sierra Mosca trail is steep, about 1100 feet drop in elevation. - General Issues: Some deadfall, overgrown and non-existent trails, and the current trail does not follow the map location in some places. The trails to the summit of both peaks have very little deadfall. A logging crew was working a nasty section of the Sierra Mosca trail that follows the Rito Con Agua the day I..." — fredbrown585 • Aug 30, 2020

"I have been contemplating hiking Sierra Mosca and Peak 11,821 for the last 2 years. I had one failed attempt after work last year because of a nonexistent trail. I relocated that same day and did The Dome. Another time, while doing Peak 11,116, I was going to add an extra night to my trip, and come in directly from the east, but lost my cell phone and was not able to contact family to say I would be a day delayed, so I did not do the peaks then. I was going to go one week earlier, that morning it was raining and going to be raining for 2 days, so did not go then. I studied every possible way and came to the conclusion that they were going to be very difficult peaks to attain no matter which way I went. I resolved to have 2 very hard days of hiking. I can now see why few people have done these 2 peaks. I was a little psyched out about doing the peaks because I had a sense of the work involved. I would be carrying a full backpack the entire time and many of the trails on the map did not exist and it would take plenty of hard bushwhacking. On Wednesday morning July 23, 2014 I left the house at 5:00 AM. I did not take my dog Daisy because I knew it would be a very difficult hike fo..." — Phil-Robinson • Jul 23, 2014