I heard that a few years back, this old-skol hippy/commune-like family in Northern California made close to 70% of all acid available at the time, for years, but they were busted by the feds and since then, Cid has been tougher to find, but it's still out there.
There's much more detail about this story, but it can be found through Google for those seeking more info on it.
Concerts and summer festivals are always a great place to start looking...but like wiser folk than I have said, if you go there, it'll find you before you know it.
And don't try making acid.
Waaaaay more trouble than it's worth. You can look online on how to do it, but you need a lot of equipment if you wanna do it right, but more than equipment, you need the knowledge on how to use that equipment without killing yourself or someone else.
You wanna be safe, both while making and taking acid, and unless you have a lot of chemistry experience and are comfortable working in a lab-setting, I'd try to find a source for finished cid from someone you trust.
It's a worthwhile journey down the rabbit hole. You'll learn a lot about yourself. Just make sure to have some cannabis, water, and Vitamin C with you. And get plenty of rest and eat beforehand....because you're not gonna sleep or eat for almost a day if you do find good acid.
Good luck and have fun!