Bodie

Bodie is one of the most incredible historic sites we've seen in the U.S.
Rather than describing it myself, I'll let the State Park brochure do the talking:

The town of Bodie rose to prominence with the decline of mining along the western slope of the Sierra Nevada. Prospecgtors crossing the eastern slope in 1859 to search for gold made a rich discovery at Virginia City. This huge gold strike, later to be known as the Comstock Lode, started a wild rush to the surrounding high desert country.
By 1879, Bodie boasted a population of about 10,000 and was second to none for wickedness, badmen, and "the worst climate out of doors".The phrase "Goodbye God, I'm going to Bodie" came to be known throughout the West.
Killings occured with monotonous regularity, sometimes becoming almost daily events. The fire bell which tolled the ages of the deceased when they were buried, rang often and long. Robberies, stage holdups and street fights provided variety, and the town's 65 saloons offered many opportunities for relaxation after hard days of work in the mines. The Reverend F.M. Warrington saw it in 1881 as "a sea of sin, lashed by the tempests of lust and passion."
Bad men, like bad whiskey and bad climate were endemic to the area but the streets are quiet now. Only about 5% of the buildings it contained during its 1880s heyday still remain and, with more than 70 buildings still standing, its clear that during the gold rush in Bodie, this was an incredible town in one of the most remote spots in the Sierra.
Today, it stands just as time, fire, and the elements have left it -- a genuine California gold mining ghost town. Designated a state historic park in 1962, it is now maintained in a state of "arrested decay".