Mount San Antonio [10,064'], colloquially referred to as Mount Baldy, is the highest peak of the San Gabriel Mountains, and the highest point in Los Angeles County, California. The peak is within the San Gabriel Mountains National Monument and Angeles National Forest.
Mount San Antonio's sometimes snow-capped peaks are visible on clear days and dominate the view of the Los Angeles Basin skyline.
The peak is pyramid shaped, with a steep south face (Baldy Bowl) and a shallower north face. The summit is accessible via a number of connecting ridges along hiking trails from the north, east, south and southwest.
FKTs have been reported for the Bear Canyon route. The ascent via this route has a Strava segment. Of course times reported on Strava are approximate, so it's best to report your precise time here. Also, the segment appears to end 10-15s short of the true summit (FKT is to the actual summit plaque).
Another Variation is an 11-mile lollipop loop starting and ending at Falls Road, as described in details with pictures and video on this highly ranked link: https://hikingguy.com/hiking-trails/best-la-hikes/mt-baldy-hike/ From the intersection of Falls Rd & Mt Baldy Rd, go up Falls Rd just beneath the bathroom and follow Baldy Road. Make sure to take a look at the falls on the left. Around mile 3 make a left on Bentley's Dream and you will shortly reach the Notch Restaurant where you can get some water. This area is a bit of a maze, so it's best to use some navigation there. You have to basically go up Mount Baldy Road that is aligned with the Bentley's Dream road you just came from. Shortly thereafter make a left on the very steep Devils Backbone Road. At the end of the ski area, the road becomes the Devils Backbone Trail. At some point there is an intersection; stay on the right going up. Further up there is another intersection. This time stay on the left, no need to go up to Mt Hardwood. After about 7 miles you will have arrived at the top of Mt Baldy. The distance may vary depending on the way you take on the large areas after the Notch since the trail is not exactly marked in those sections. Make sure to enjoy the views at the top there before looking for the sign that says Sierra Club Ski Hut and Maker Campground. Go down this rugged trail. There is a stream of fresh water around mile 8.5 by the ski hut. Continue on this trail until you hit Baldy Road. Go down to the right and you'll reach the starting point at the bottom of Falls Rd. NOTE: It came to our attention that there is also a Strava Segment for the Loop, with some fast times. Please consider the Strava times if you are going for an FKT!
Sea to Summit: An open course starting at the ocean (Santa Monica Beach is suggested, but you can choose your own starting point) and running to the top of Mt Baldy (you will have to get back down to the TH, but the clock stops at the top). Approx 78 miles.
Admin note: Seal Beach was suggested as a starting point for sea to summit by username Baldy_4748. "Seal Beach > S.G.R.T. North > Todd Ave exit > Left on Sierra Madre > Right on Valley Center > Left on Foothill Blvd > Right on Ameila > Left on Route 66 > Left on Baseline > Left on Mills > Right on Mt. Baldy Rd. > Ride ends just before the ski lift sign (end of the road) at Manker Flats > Ski Hut Trail > Summit. GPX says 10,773 E.G. but it's more like 11,300. I've done this route twice. The first time I took Register Ridge up to the summit. I've also done this from Huntington Beach four times in conjunction with the annual Labor Day R2T race. Seal Beach entails way less navigation, lights and traffic. Time to the plaque was 8 hrs 09 min at a comfortable pace. FKT is 6 hrs flat by Don Bowie. Not sure what else to say. Pretty straight forward. Have fun."