In the summer and fall of 1868, continuing their annual seasonal raiding activities between the Arkansas and Platte Rivers in what was also the region of their best buffalo hunting, bands of Cheyenne and Arapaho Indians conducted raids against whites throughout the western Great Plains in Kansas. In addition, they found incentive in the warfare that had been waged specifically against their clans by the military in 1867 and by memories of such atrocities as the Sand Creek massacre. Finally, the westward movement of the transcontinental railroad had stretched all the way across Kansas, bringing with it many permanent white settlements.