Sutter’s Mill is a replica Sawmill located in Coloma at the Marshall Gold Discovery State Historic Park. Though it is not a gold mill it has a strong tie to gold in California. It was here, were water drained away from the mill that James Marshall found several 23k gold nuggets laying in the American River. The mill is a fascinating piece of 1800’s technology.
The park also has a two stamp mill on display. Comment below if you have been!