The Sturtevant Falls Trail is one of the most popular hikes in the San Gabriel Mountains at Chantry Flat Road, Arcadia, CA 91006. Just take Santa Anita to the top of the mountain, and you will see a parking lot (there is a fee) and a store. Parking is limited so go early!
There is a waterfall at the trail's end; I went in late November when it was still a bit hot in L.A. There was not much water. But the trail was gorgeous, there's a water dam, cabins, and bridges along the way, so it makes it a fascinating hike.
I wondered what the cabins were for the whole time and found out you can actually rent the cabins on the trail. Here is some information in case you were wondering the same thing.
Distance: 3 miles
Elevation Gain: 646 feet
Route Type: Out & Back