The Mystery of Lost Lake of the Cajon Pass

It is not known to many people, but it is still possible to use the old highway up through a portion of the Cajon Pass. Present day highway 15 runs well above old 395 and Historic Route Highway 66. Such rustic areas as Blue Cut and Halls Ranch (Yes my Family again), and Sullivan's Curve still exist.

As you drive up the badly surfaced road from Devore (Use the Kenwood Exit from the Northbound 15 and make a left, pass under the 15 and then make a right on Cajon Blvd [old 395 & route 66]) you notice that for the most part you are driving on what would be the southbound lanes of the old 4 lane highway. As you come around the curve at Blue Cut you notice that there is now a mountain sitting over the right-hand lanes into the center divider. You might think that this is ample proof that the San Andreas Fault zone is alive and moving. But you would be wrong. It is actually the San Jacinto Fault Zone that straddles the highway. The San Andreas is still one mile ahead.
Two Faults zones so close together and visible? As you proceed north you notice that the entire area between the faults is moving to the north and at different speeds. Only 2 or 3 inches a year, but they are moving. So much so, that railroad crews from both the Union Pacific and Burlington Northern Santa Fe, have to go out twice a year and reset the tracks. Otherwise, the train tracks would bend out of shape, just like old 395 has.

As you proceed, you will see a sign that says 'Lost Lake'. It also says private road so most people ignore it and just keep heading up towards Sullivan's Curve. Sullivan's Curve by the way, is a favorite Train Watcher area and has also been the scene of several major train accidents over the years. The best way to get into this area is to exit highway 15 at Cleghorn Pass Road, make a left under the freeway if you are going north bound that is and then make a right on the first roadway you see. This will take you back to a triple track bypass area, a small yard, and the beginning of the lower end of Sullivan's Curve.

But if you take the time to make the left turn onto the dirt road and cross the triple set of tracks that tend to hide it's route, you eventually find a quiet little area that should not exist. For there are no streams, creeks or rivers that feed into Lost Lake. The water seeps up from beneath the ground. A direct result of two major earthquake faults zones passing within a half mile of each other.

Some say that Lost Lake has no bottom, that it feeds directly from the center of the earth. The water is also very cold, below freezing even in summer time. Fire crews have used its water supply to help fight fires, and they have never noticed a drop in water levels. It always stays the same, even in heavy rain seasons. And snow fall has no effect on it. But it has never frozen either.

Lost Lake is surrounded by lush grassy vegetation, some what like what you might see back in Kentucky or Tennessee. In fact Kentucky Blue Grass grows all around the lake.

As you drive further into the narrow valley you realize that both fault zones are coming together. All of a sudden you run into a wall of a mountain that blocks your way. You can climb up this 500 foot high rock fall and look out over the valley you have just passed through. To the northwest are the 10,000 peaks of Mt Baldy, Cracka Ridge and the Mountain High Ski area. As you hike through the area you become aware of how insignificant you are amongst the grander of the Fault Zones, the Mountains and the trees.


Isn't there a lost lake in jurupa hills in fontana/bloomington i heard the
bottom of the lake never ends

LOST LAKE is not bottomless. It is probably spring fed and possibly on the San Andreas fault.
Read the post on 3/23, where the author waded into 3' to 5' depth water.

Not probably.. Lost Lake is smack-dab in the middle of the San Andreas fault, which runs right through the Cajon Pass.

How deep is the lake now?


in the 70's it seemed like a really cool place. the lake now is very smelly and creepy. do not take your family there. its no place for decent people to be hanging out,i mean it. the lake is 3 to 8 ft deep. a lot of wierdo's consume the whole 2 mile area around the lake now. so seriously,dont take your family around there. i went up there last summer and the lake and area is awful. like the guy wrote in the other comments,take a gun if you do decide to go there. very dirty place,just go somewhere else. seriously.

So Lost Lake is about to be a dry lake. Water level way down you can walk across is and only get about knee deep. So much for no bottom..

4 years go we enjoyed a beautiful spring afternoon at Lost Lake. Now 2 days ago my son decided to go there for senior ditch day and was very disappointed that the lake is practically dried up! There's only about a foot of water left! There were dead fish and a dead turtle! The drought is real my friends!!

05/22/15 Where has all the water gone? Can't believe the lake has been lost, almost 30' wide an 2' deep! Probably was used to fight fire last year but should have refilled?? Think we're getting ready for the big earthquake.

My Grandfather was a Cowboy and we own property in Wrightwood. We would go gold panning out there and hang out at the stream along the tracks. But when my grandfather took us to Lost Lake for my first time it was happening. Everybody would hang out & back there cars up to the lake and swim and party. I remember Hells Angels would always be there having a good time. One time I saw my grandfather jump in and saved a girl from drowning. But what I remember when I looked in water at the bottom was a bunch of CARS and we were all swimming in it!!!! Does anybody remember that????? I still tell that story till today and I also tell people that u are able to see Satellites out there moving when u stare at the Stars. It's amazing beautiful and Dark!! I learned to hunt, gold panning and how to survive out there eating quails & rattle snakes. My Grandpa was a Cowboy!!!!


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