How many of these are there in the USA, anyway? Seems anywhere I go there's a Lost Dutchman mine nearby, or the equivalent.

I lost mine, can't remember where I left it.

AZ has at least one. That area does a pretty decent job at killing tourists as well.

Only one I knew of was in AZ.

Yup, and guess what... He wasn't Dutch, he was German. It was common for early American to mix up Deutschland and Dutch, calling German people Dutch.

Yeah, it's behind my house, in the Superstition Mountains.

Loads of people every year look for the rumored gold, none have found it.  People die or get killed over it all the same.

I'm pretty convinced that Walz (or however his name was spelled) was finding his gold nearer to ,or actually IN, the town of Goldfield. There was a working mine there that was paying off handsomely until the water table rose and flooded it. Those shafts are still full of water and inaccessible, but are said to certainly be worth the squeeze if the water could be controlled. The same thing killed silver mining in Tombstone. You can tour one of the pits that didn't flood if you visit the Goldfield tourist trap. While you're there, visit the Mammoth Saloon, which is the best use of your money anywhere near Apache Junction, AZ.