1850-1900

1858 - discovery of Gold in Colorado brings flood of miners and settlers to traditional Arapaho wintering grounds around Denver

1864 - Sand Creek Massacre occurs near Arkansas River - Arapahos and Cheyennes attacked while under truce flag

1867 - Southern Arapahos agree to move to a reservation in western Oklahoma

1878 - Northern Arapahos agree to move to a reservation in western Wyoming