Illinois Local Business Directory

Portions of the area that would later become Illinois were mapped by Jacques Marquette and Louis Jolliet on behalf of France in 1673. The two explorers traveled along the Illinois River and painstakingly recreated its course through the region. To solidify their claim and control over the area, later French settlers established a number of fortifications and villages along the Mississippi River. The area changed hands on a few occasions before its transfer to the United States in 1783 and its establishment as part of the Northwest Territory of the U.S. Illinois joined the Union in 1818 as the 21st state.

Chicago is the largest city in Illinois and the third largest by population in the U.S. From its earliest days, Chicago represented a center for industry in the nation and provided strategic support for Union troops during the Civil War. The discovery of oil in Marion and Crawford Counties in 1937 increased the population of Illinois considerably as immigrants seeking work flocked to the state. As a center for military research and development, Illinois was an important location for research into the nuclear bomb. The state was also instrumental in developing nuclear power plants and was the site for Fermilab's particle accelerator; located near Batavia, Fermilab's accelerator was the largest in the world for many years.

Today, Illinois maintains a diverse economy that includes agricultural production, manufacturing plants and service-related businesses. The first McDonald's in the world was established in 1950 by Ray Kroc in Des Plaines. Both the Chicago Cubs and the Chicago White Sox baseball teams are based in Illinois, and fans cheer for the NFL Chicago Bears and the Chicago Bulls basketball team at home games held in stadiums and fields around the city.