Apart from the small French settlements along the Mississippi River that were formed in the 18th century, most early white migration into Illinois came from the South, as poor young farm families trekked overland to southern Illinois from Kentucky, Tennessee, and the Carolinas between 1800 and 1840. After 1830, migration from Indiana, Ohio, and Pennsylvania filled the central portion of the state, while New Englanders and New Yorkers came to the northern portion.
Immigration from Europe became significant in the 1840s and continued in a heavy stream for about 80 years. Before 1890, most of the new arrivals came from Germany, Ireland, Britain, and Scandinavia. These groups continued to arrive after 1890, but they were soon outnumbered by heavy immigration from southern and eastern Europe. The opening of prairie farms, the burgeoning of towns and small cities, and the explosive growth of Chicago created a continuous demand for unskilled and semiskilled labor. Concern for the welfare of these newcomers led to the establishment of Hull House (1889) by Jane Addams in Chicago. Hull House served as a social center, shelter, and advocate for immigrants. Launching the settlement movement in America, its activities helped popularize the concept of cultural pluralism. The University of Chicago was one of the first major universities to concern itself with urban ecology and with the tendency to "ghettoize" culturally and economically disadvantaged populations.
The outbreak of World War I interrupted the flow of European immigrants but also increased the economy's demand for unskilled labor. The migration of blacks from states south of Illinois—especially from Arkansas, Tennessee, Louisiana, Mississippi, and Alabama—played an important role in meeting the demand for labor during both world wars. After World War II, the further collapse of the cotton labor market drove hundreds of thousands more blacks to Chicago and other northern cities.
In contrast to the pattern of foreign and black migration to Illinois was the continued westward search by native-born whites for new farmland, a phenomenon that produced a net outflow by this group from 1870 to 1920. After World War II, native whites again left the state in large numbers, with southern California as a favorite mecca. After 1970 for the first time, more blacks began leaving than entering Illinois.
The major intrastate migration pattern has been from farms to towns. Apart from blacks, who migrated considerable distances from farms in the South, most ex-farmers moved only 10–30 mi (16–48 km) to the nearest town or city.
During the 1970s the state lost 649,000 persons in net migration, for an annual rate of 0.5%. From 1980 to 1983, the net loss from migration totaled 212,000, or 0.6% annually. From 1985 to 1990, the net loss from migration came to 139,360. Between 1990 and 1998, there was a net loss of 516,000 persons from domestic migration and a net gain of 337,000 from international migration. In 1998, 33,163 immigrants from foreign countries arrived in Illinois, the 6th-highest number for any state and over 5% of all foreign immigration to the US for that year. The greatest number of foreign-born residents that year came from Mexico, totaling 10,127. In 1998, the Illinois Hispanic population numbered 1,145,000 while those of Hispanic origin numbered 1,224,000. Between 1990 and 1998, the state's overall population increased 5.4%. In the period 1995–2000, 665,122 people moved into the state and 1,007,738 moved out, for a net loss of 342,616.