American Indian Wars: Battle of the Little Bighorn: 300 men of the U.S. 7th Cavalry Regiment under Lieutenant Colonel George Armstrong Custer are wiped out by 5,000 Lakota, Cheyenne and Arapaho, led by Sitting Bull and Crazy Horse.

The American Indian Wars, also known as the American Frontier Wars, and the Indian Wars, were initially fought by European colonial empires, the United States, and briefly the Confederate States of America and Republic of Texas against various American Indian tribes in North America. These conflicts occurred from the time of the earliest colonial settlements in the 17th century until the end of the 19th century. The various wars resulted from a wide variety of factors, the most common being the desire of settlers and governments for Indian tribes' lands. The European powers and their colonies enlisted allied Indian tribes to help them conduct warfare against each other's colonial settlements. After the American Revolution, many conflicts were local to specific states or regions and frequently involved disputes over land use; some entailed cycles of violent reprisal.