Illinois Indians (Illinois, through the French, from Illini-wek, i.e., men: the name used by themselves), an important confederacy of Algonquian tribes formerly occupying the greater part of the present state of Illinois, together with the adjacent portion of Wisconsin, Iowa, and Missouri. Their language, which was perhaps the softest of all the Algonquian tongues, differed only dialectically from that of the Miami, their eastern neighbors and usual allies. They probably numbered originally from 8000 to 10,000 souls, in five principal sub-tribes, the Cahokia, Kaskaskia, Michigamea, Peoria, and Tamaroa. Physically the early Illinois are described as tall, robust and well-featured, but lacking in courage and steadiness of purpose, and greatly given to licentiousness. The priests and conjurors seem to have been even more influential among them than in other tribes. They were rather hunters than farmers and seldom kept their villages long in one place. Their houses were long communal cabins, with four to five fires ranged along the central passage, each fire accommodating two families. The great village of the combined tribes in 1692 was estimated by Father Rasle to contain 300 such cabins,—hile other explorers of about the same period reported as high as 400. Polygamy was common, a man sometimes marrying several sisters of the same family, and they appear to have had the clan system. Among their great ceremonies was the noted Calumet dance, the special aversion of the missionaries, which spread from the Illinois to all the tribes of the central region. Their dead were generally disposed of by being wrapped in skins and fastened upright to trees. They carried on a defensive war against most of the surrounding tribes, as well as against the invading Iroquois, but were uniformly friendly toward the French and the English.
So far as known the first white man to make the acquaintance of the Illinois was the Jesuit pioneer, Father Claude Allouez, who met them as visitors at his mission at La Pointe (Hayfield, Wis.) in 1667, and again at the Mascoutens village in southern Wisconsin three years later. In 1673 Marquette, on his voyage of discovery down the Mississippi, was welcomed by them about the mouth of the Des Moines in Iowa, and on his return passed through their villages on the Illinois, preaching as he went. He had already made a study of the language, at La Pointe, in anticipation of establishing a mission, as they now requested. Permission being given, he set up his altar, dedicated to the Immaculate Conception, among the Kaskaskia in April, 1675, but died a month later while on his way to Mackinaw. The work was taken up by Allouez, but again discontinued owing to the Iroquois inroads and the opposition of La Salle, who brought in three Recollect missionaries—Fathers La Ribourde, Membre, and Hennepin. They found little encouragement, however, and Father La Ribourde being slain by a roving war party, the Recollect attempt was abandoned. In 1684 Allouez returned and resumed work among the Peoria gathered at the French fort at the head of Peoria Lake (Rockfort, Ill.). He was followed by Gravier (1687), Rasles (1692), and again by Gravier (1693), to whom we owe the first grammar and dictionary of the language. Father Gravier died in 1706 from a wound received in an encounter with a heathen mob. A second mission was founded about 1700 among the Tamaroa, near the French post of Cahokia, nearly opposite St. Louis, and another about the same time among the Kaskaskia. Twice a year, for a few weeks in summer and for a longer period in winter, all the bands left their villages for the buffalo hunt and were followed by the missionaries. When visited by Charlevoix in 1721 the missions were jointly under the care of Jesuits and priests of the Seminary of Foreign Missions. The Peoria were still almost all pagan, as were portions of the other tribes, but the majority were now Christian, and intermarriage with the French settlers had become common. About this time several of the nation, including the chief, Chicago, visited France and were much impressed by what they saw.
In spite of their receptive temperament the Illinois were fickle, and intemperance introduced by the French garrisons did much to nullify the work of the missionaries and demoralize the tribes. As allies of the French against the hostile Chickasaw and Natchez of the lower Mississippi, they suffered heavily. In 1730 a detachment accompanied the ill-fated expedition of d'Artaguettes against the Chickasaw, and among the prisoners who suffered a horrible death at the stake was the devoted Jesuit missionary, Senat. By this time invasion by the northern tribes and wholesale dissipation at home were rapidly thinning the number of the Illinois, and in 1750 they had been reduced to about 1000 souls with apparently but one mission. The priests of the Foreign Missions were now devoting themselves entirely to the French. On the transfer of Louisiana to Spain in 1763 the Jesuit missions, including those of the Illinois country, were suppressed and confiscated, although the missionaries generally remained as secular priests. The murder of the celebrated chief Pontiac, by a Kas-kaskia Indian bribed by an English trader, brought down upon the Illinois the swift vengeance of the confederated northern tribes, who began a war of extermination that in a few years reduced the nation to a handful of refugees among the French settlements. In 1778 there remained only 380 in two villages in the neighborhood of Kaskaskia, completely demoralized by drunkenness. In 1833 the survivors, represented by Kaskaskia and Peoria, sold their remaining lands in Illinois and removed to northeast Oklahoma, where they are now confederated with the remnant of the Wea and Piankishaw (part of the Miami), under the official designation of "Peoria and confederated tribes", the entire body numbering in 1908 only 204, all of mixed white blood, but still retaining some share of their language and their Catholic inheritance.