"In the 19'th century the american government encouraged settlers to go into the far west. At the same time they also made promises to the exiles natives from the east to find new homes in the west.
More and more Europeans came into the new world. Between 1840 and 1860 more than 4.000.000 settlers reached the United States." (4)

"California became too small, so that soldiers of fortune, speculators and gambler went over the mountains to east and north. They fell upon Montana in 1862/63 when gold was found in Bannack and Alder Gulch, upon the Black Hills after lieutenant-colonel Georg A.Custer and his regiment confirmed rumors about lots of gold deposits in 1874.
The following development was often the same: not only gold were found but other mineral resources like silver, copper or coal. Camps and provisional settlements grew very fast and became dilapidated to ghost towns as well." (5)

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How fascinated are ghost towns may be to todays visitors, but they are silent witnesses of a history of expulsion and extinguishing of the Natives.
Elkhorn is only one of many examples.