El Dorado, Spanish for "Golden One", was one of the original 27 Counties of the State of California. These 27 County boundaries were conformed as a matter of an Act, signed February 18, 1850. Though there were many discoveries of precious metals in the area now known as the State of California, the discovery of gold in Coloma on January 19, 1848 by James W. Marshall produced "gold fever", and the population exploded as hoards of men swarmed into the area.
Click here for more info.
Click here for more info.