Bonita Falls is one of those waterfalls where you really have to look past its flaws (most of which were human-induced) in order to appreciate its true beauty and the fun experience to get to it.
This waterfall is one of the taller waterfalls in Southern California as it's said to have a cumulative drop of some 400ft. However, I was only able to see its final 90ft drop from its base as well as a very distant view of one of its upper drops (possibly 100ft or higher) from a nearby private campground turnoff. Adding to the allure of this waterfall was the adventure I had to go through involving a fording of Lytle Creek, a rough boulder scramble in a wash, and then a little bit of some rock scrambling to get right in front of the falls.
The only real bummer with this falls was the presence of insane amounts of graffiti and litter all throughout the hike (you might have guessed this already from looking at the photos on this page). Although I've seen such poor displays of respect for Nature in places like Eaton Canyon Falls and Hermit Falls, I think this one by far takes home the crown for the most trashed waterfall I've been to so far in the Southland.
It's really sad that such a beautiful place like this can degenerate into something you'd expect to see in the hood, but I guess it goes to show you how fragile Nature can be, and how easy it is to ruin a good thing when you let it. I personally hope the San Bernardino Forest Service can do something about it, but I wonder how resource-limited the National Forest Service is, especially when it's close enough to the foothill cities like Rancho Cucamonga to allow urban blight to creep in and constantly put pressure on the resources necessary to enforce rules and clean up the mess that's here.
The adventure started after parking the car in one of the pullouts in the area around the confluence of Middle Fork and South Fork of Lytle Creek (see directions below). Then, I had to look for a place to cross Lytle Creek in order to access the wash on the other side. I thought the initial creek crossing was treacherous enough that I felt compelled to employ river crossing techniques seen in survival shows (or at least be willing to turn back if the creek was deeper than my thighs). By river crossing techniques, I meant that I had to look for the widest part of the creek or river, unhook the waist belt of my pack, face upstream, and use a stick for added balance. For added comfort (and to prevent ruining my hiking boots), I actually crossed Lytle Creek in Keens and then changed into hiking boots once I got past the creek crossing.
The hiking boots were definitely necessary because the next phase of the adventure involved walking a wide and bouldery wash. It was here that the thought of twisting my ankle did cross my mind, even though I was wearing proper footwear.
So while in the wash, I made a beeline for the south wall of the South Fork of Lytle Creek. The south wall was the nearest wall to me after the creek crossing. Once I was by the south wall, I continued heading in the upstream direction for the next half-mile or so. I found that hugging the south wall was a bit flatter and sandier than the boulder-laden middle of the wash. That also helped me minimize my chances of missing the easy-to-miss foot path to the left into the drainage containing Bonita Falls (which I knew was in that general direction from looking at the maps prior to my visit).
Once the faint, easy-to-miss footpath was reached in about a half-mile from the creek crossing (I saw a reassuring sign at this spur trail even though there were lots of graffiti on it), I followed it further upstream for another 10 minutes or so until I reached the base of Bonita Falls. This last 10 minutes of walking and scrambling got steeper with plenty of deadfall obstacles, but fortunately there were some rock steps as well as detours around the obstacles to make this last section of the hike not as difficult as it could've been without this apparent trail maintenance.
At the base of the falls, I noticed that it was possible to make a somewhat non-trivial scramble alongside one of its lower cascades to get right up to its base. It was here that I appreciated just how defiled the otherwise beautiful waterfall was as it was surrounded by rock walls that were covered in spray-paint graffiti.
In addition to the falls, I also made a steep scramble up the south side of the canyon (before the final cove containing the waterfall itself) up to where there was a trio of caves as well as the possibility of glimpsing the main waterfall rising above the foliage. I only managed to scramble up to two of the three caves and didn't see the upper tier during my visit. But like the rest of this side canyon, these caves were also loaded with graffiti. I even noticed toilet paper soiled with poop left here as well.
All in all, it took me roughly 30 to 45 minutes in each direction to cover the roughly 1.5- to 2-mile return hike and scramble.
From the Los Angeles basin, you can drive east on any of the eastbound Freeways (e.g. the 10 Freeway, 60 Freeway, or the 91 Freeway) until it reaches to I-15 going north (kind of like you were going to Vegas). However, as you drive north the I-15, exit Sierra Ave then turn left to go deeper into the mountains. Eventually, Sierra Ave becomes Lytle Creek Road.
Continue taking Lytle Creek Road for a little over 6 miles from the I-15. Once you've gone past the Lytle Creek Ranger Station (you can also buy Forest Adventure Passes here), then start looking for a pullout (not signposted) with a bear-proof trash bin between the Green Mountain Ranch sign and the Bonita Ranch RV & Campground sign.
The adventure described above on this page begins from this pullout.
Now if you're curious about getting a distant (but unsatisfactory) view of one of the upper tiers of the falls, you might be able to spot it once you turnoff towards the private Bonita Ranch Campground (just a short distance west of the unsigned pullout to start the hike). However, be cognizant that the owners and guests do not appreciate you blocking traffic in order to catch this view.