Population. The Territory of Illinois in 1810 had 12,282 inhabitants. The population of the State by decades is as follows: In 1820, 55,211; 1830, 157,445; 1840, 476,183; 1850, 851,470; 1860, 1,711,951; 1870, 2,539,891; 1880, 3,077,871; 1890, 3,816,351; 1900, 4,821,550. The rank of the State advanced from eleventh in 1850 to fourth in 1860 and third in 1890, which position it still holds. In 1890 it surpassed Ohio for the first time, and became the most populous State west of the Alleghany Mountains. The greatest absolute gain was made in the last decade of the century, the per cent. of increase being 26.0, as compared with 20.7 for the United States. The earlier movements of population into the State were largely composed of Southerners, who crossed the Ohio River into southern Illinois, or were attracted up the Mississippi River to the lead-mining districts in the northwestern part of the State. These, however, were soon greatly outnumbered by immigrants from the Eastern States. Some of the public lands were still unoccupied when the great German migration to America began, and consequently a large number of Germans found homes within the State, and Chicago has continued to be a German centre. The German born are considerably more than twice as numerous as any other foreign nationality, and constitute over one-third of the total foreign-born population. The Scandinavians came a little later, yet in time to secure a firm foothold in the northern part of the State. The Irish element is much less prominent than in the Atlantic Coast States, but is about equal to the Scandinavians in numbers. The more recent immigrants include a large number who are of the Slav or Latin race. The total foreign-born population in 1900 numbered 966,747. The colored population numbered 86,677, of whom 1503 were Chinese. The urban population equals half the total for the State, and the gain during the last decade has been wholly in the towns and cities, the per cent. of gain in these being 53.2. Sixty-six places exceed 4000 in number of inhabitants. The density of population is 86 per square mile, or more than three times that of the nation as a whole. The male sex outnumbers the females by 125,000.
Cities. According to the census of 1900, the cities having a population exceeding 25,000 are as follows: Chicago, 1,698,575; Peoria, 56,100; Quincy, 36,252; Springfield, 34,159; Rockford, 31,051; East Saint Louis, 29,655; Joliet, 29,353.
Religion. Estimated upon the reported number of church communicants, the Methodists about equal the Catholics in their adherents. The Baptists, Disciples of Christ, Presbyterians, German Evangelicals, Congregationalists, Lutherans (General Council), and Protestant Episcopalians follow in importance in the order named.
Education. In 1900 only 4.2 per cent. of the population over ten years of age were illiterate, as compared with 10.7 for the whole country, The free-school system dates from 1855. Rapid progress has been made in perfecting the system, especially in lengthening the school year, the average for recent vears having exceeded 150 days. The power of the county superintendent has been increased so that he can supervise the schools without restriction by the county boards. Great inequalities, however, exist throughout the State, due to the inadequacy of local taxes in many of the rural communities, and to lack of centralization. Over 350 schools enroll fewer than 10 pupils each. Lack of funds necessitates short terms and leads to the employment of mediocre teachers. More than one-third of the pupils of the State are enrolled in ungraded schools. The lack of high schools in the rural communities, or any provision for the payment of their tuition in schools outside their district, prevents many from securing the advantages of a secondary education. In 1900 there were 1,588,000 persons between the ages of six and twenty-one. Of these, 958,900 were enrolled in the public schools, the average attendance being 737,576. The per cent. of the children in daily attendance increased from 61 in 1880 to 76.9 in 1900; and the average number of days attendance increased during the period from 91.9 to 123.3. There were also 142,496 children enrolled in 965 private schools. The private secondary schools numbered 65, and the public high schools 321. The public-school teachers numbered 26,303, of whom 6950 were male. The average monthly salary of the male teacher was $60.34, and of the female teacher $52.45.
The total cost to the State of the public schools and educational institutions was, in 1900, $19,919,000. The income from the township school funds amounted to $900,000, while that from the county and State funds approximated $100,000. The average cost per enrolled child was $18.94. The total permanent school fund now amounts to $17,429,000. The largest items are, first, school lands unsold and other lands of an estimated value of $9,571,000, and, second, the township funds, being the net proceeds of the sale of the sixteenth section in each Congressional township, amounting to $5,923,000. The State educational system comprehends higher institutions of learning, of which there are five normal schools, located respectively at Charleston, De Kalb, Macomb, Carbondale, and Normal; an agriculture and mechanic-arts school at Urbana; and a university also at Urbana. In few States has private initiative been more active in establishing higher schools of learning. Thirty-one institutions have assumed the name of ‘college’ or ‘university.’ Besides these there are a large number of professional and technical institutions, more modest in name, but equally well known. Cook County Normal School is one of the best known in the whole country, and the University of Chicago (q.v.) has attracted wide attention by its original features and the eminence of the scholars who have been called to fill its chairs. Among the best known of the other institutions are the Northwestern University, the Armour Institute of Technology, and the Rush Medical College, situated at Chicago; Knox College, at Galesburg; and Illinois Wesleyan University, at Blonmington. Most of the higher institutions are coeducational.
Charitable and Penal Institutions. The following is a list of the correctional and charitable institutions of the State, with their situations:
| Correctional | Situation |
| Penitentiary (Northern) | Joliet |
| Penitentiary (Southern) | Chester |
| State Reformatory | Pontiac |
| State Training School for Girls | Geneva |
| Charitable | |
| Illinois School for the Deaf | Jacksonville |
| Institution for the Education of the Blind | Jacksonville |
| Central Hospital for the Insane | Jacksonville |
| Soldiers' Orphans' Home | Normal |
| Asylum for Feeble-Minded Children | Lincoln |
