Colonel John Chivington and his Colorado volunteers carried out a brutal assault on a peaceful village of Cheyenne and Arapaho people at Sand Creek in the Colorado Territory. Prior to the attack, the Native American tribes had established a camp and were under the impression that they would be safe after having recently received reassurances from U.S. military authorities. Nevertheless, on November 29, a group of around 700 Colorado militia troops, fueled by fears and suggestions from local settlers, approached the camp, despite its peaceful status. What followed was a horrendous massacre where soldiers killed, mutilated, and subjected the villagers to atrocities. Out of an estimated 150 victims, most were women, children, and elderly individuals, as the male warriors were often away from the camp hunting or attending other duties.

The Sand Creek Massacre became a flashpoint for the escalating conflict between the United States government and Indigenous tribes, which had been building for years over issues of land, treaties, and sovereignty. The aftermath revealed a deep-seated brutality that characterized many aspects of frontier conflict during this period. It also spurred outraged responses, such as the formation of groups supporting the rights of Native Americans and advocating against such violence. The massacre was widely condemned in the long run, leading to investigations and changes in U.S. policy toward Native American relations.

The story of Sand Creek remains significant in discussions of American history, reflecting themes of genocide, colonialism, and the complex relationships between indigenous peoples and settlers. It is remembered as a somber chapter in the annals of U.S. expansionism and entails ongoing discussions about reparations and recognition for Native American tribes.