About thirty miles southeast of San Francisco is my hometown of Castro Valley. Almost everybody from my generation who grew up in Castro Valley remembers hearing about the nuclear guided missile site above Lake Chabot; officially called Site SF-31. I think the first person to tell me about it was one of my childhood friends named Ron. I think he embellished it a little by telling me he had seen test rockets fired from there, but that probably didn’t happen. However, even as a kid I was smart enough to know that if the base was a missile site, it was also a target site. However, I decided not to run away. Yesterday morning I took an e-bike ride up to the old missile site. (Thumbnail images)
A nice view of Lake Chabot on the way up: 
Looking over the missile base toward Lake Chabot in an old photo from Military Historian, Dan Sebby of the California Military Department:
I wanted to get to the top so I rode past this first RESTRICTED AREA sign, risking a ticket. 50 years ago I probably would have been shot for doing that.
The heliport at the top must still be in use. They probably had frequent high-profile visitors arriving here at this spot when the base was active; you know, like Nikita Khrushchev.
This was where the nuclear missile launching pads were; straight on back past the green trucks. I decided not to risk getting a ticket this time, and didn’t go beyond this point.
Another aerial photo of the base from Military Historian, Dan Sebby, taken in 1965: I stopped at the entrance to the Missile Warhead Building area.
Still plenty of old barbed wire fencing at the top.
The type of missiles on standby at SF-31: (Dan Sebby)
San Francisco Film Locations Then & Now 
The Nike Base! We lived on the other side of the hill from it and somehow, in my 5-year old brain, I was convinced this was Cuba and during the missile crisis of the 60’s I was sure we were going to die because the missiles were so close to our house! Talk about childhood trauma! Thanks for the post!
I know what you mean, Irunning, but thankfully the base was never used for what it was intended for and we got a chance to grow up.
Oh my goodness! I would laugh about Cuba right over the hill, but when I was about five, I believed that Paris in France was right on the other side of the Golden Gate Bridge, and that Texas was in Milpitas.