CHEYENNES, a nation of Indians, being with the Blackfeet the most westerly tribe connected with the great Algonquin family. They were formerly settled on the river Chayenne or Cayenne, a branch of the Red river of the North, from which they were driven by the Sioux. They then retreated beyond the Missouri below the Warreconne, where their fortifications were long visible. Before the commencement of the present century they were driven west to the Cheyenne river near the Black Hills, and here they were found by Lewis and Clarke in 1803. Acquiring horses, they became prosperous and active, carrying their raids as far as New Mexico. In 1822 their numbers were estimated at 3,250. In 1825 Gen. Atkinson made the first treaty with them at the mouth of Teton river, establishing friendship and regulating trade, but fixing no limits. They were then at peace with the Sioux, and warring with the Pawnees, Kansas, and other tribes. Dissensions arose, and the nation separated, one part remaining with the Ogallala Sioux, and with them wresting Powder river and Tongue river valleys from the Absarokas or Crows; the other moving south to the Arkansas, where they joined the Arapahoes. In 1847 they were estimated at 5,300. By the treaty of Fort Laramie in 1851 the northern Cheyennes agreed to allow roads to be run through their territory, and arrangements were also made with the southern band. Other treaties followed, often hastily made and imperfectly understood by the Indians, to whom they were explained through a Sioux interpreter, and never fully carried out by the United States government. The multiplicity of treaties and constant change of plans excited distrust in the minds of the Indians and led to many troubles. The failure to carry out the treaty of 1861 caused a bad feeling, and hostilities were begun by the attempt of some United States troops to disarm a southern Cheyenne party in consequence of a vague complaint that animals had been stolen. The Cheyennes were for the first time arrayed against the whites, but negotiations were on foot when Col. Chivington of Colorado, Nov. 29, 1864, attacked the Sand Creek village and massacred about 100 Cheyennes, men, women, and children. The war that followed is said to have cost the government $30,000,000, and some accounts say $40,000,000. Since that time there has been constant trouble. Treaties were made in 1865 and 1867, each giving different limits. In 1865 the southern band, except a part known as the Dog Soldiers, agreed to go on a reservation. In 1867 Gen. Hancock burned the village of these last on Pawnee fork, and another war began, in which Gen. Custer defeated them at Washita, killing Black Kettle and 37 others, two thirds women and children. This war cost the lives of 300 soldiers and settlers. The northern band continued peaceable, although urged by the Sioux to join them against the whites in 1865. In fact these Cheyennes submitted to insults hard for an Indian to bear, and gave warning to the troops. They renewed treaties of peace in 1866 and 1868. The Cheyennes are now (1873) in three bodies in all cases mixed with Arapahoes, on Milk river, Montana, on the North fork of the Canadian, and a small band apart. In person the Cheyennes are a fine race, exceeding in stature all the tribes of the plains except the Osages. They are generally rich in horses and are great horse dealers. The attempts to educate them have not met with much success, the school report of 1871 showing only eight pupils, although the tribe must number 3,500 souls. Their language is extremely difficult to learn.