Illinois is the 25th most extensive and the 5th most populous of the 50 United States, and is often noted as a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal, timber, and petroleum in the south, Illinois has a broad economic base. Illinois is a major transportation hub. The Port of Chicago connects the state to other global ports from the Great Lakes, via the St. Lawrence Seaway, to the Atlantic Ocean; as well as the Great Lakes to the Mississippi River, via the Illinois River. For decades, O'Hare International Airport has ranked as one of the world's busiest airports. As the "most average state", Illinois has long had a reputation as a bellwether both in social and cultural terms and politics.
In the 1810s, settlers began arriving from Kentucky. In 1818 Illinois achieved statehood. The state's population originally grew from south to north. Chicago was founded in the 1830s on the banks of the Chicago River, one of the few natural harbors on southern Lake Michigan. Railroads and John Deere's invention of the self-scouring steel plow turned Illinois' rich prairie into some of the world's most productive and valuable farmlands, attracting immigrant farmers from Germany and Sweden. By 1900, the growth of industrial jobs in the northern cities and coal mining in the central and southern areas attracted immigrants from Eastern and Southern Europe. Illinois was an important manufacturing center during both world wars. The Great Migration established a large community of African Americans in Chicago that created the city's famous jazz and blues cultures.
Three U.S. Presidents have been elected while living in Illinois—Abraham Lincoln, Ulysses S. Grant, and Barack Obama. Additionally, President Ronald Reagan, whose political career was based in California, was the only US President actually born and raised in Illinois. Today, Illinois honors Lincoln with its official state slogan, Land of Lincoln, which has been displayed on its license plates since 1954.

 Name
"Illinois" is the modern spelling for the early French missionaries and explorers' name for the Illinois people, a name that was spelled in many different ways in the early records.
The name "Illinois" has traditionally been said to mean "man" or "men" in the Miami-Illinois language, with the original iliniwek transformed via French into Illinois. However, this etymology is not supported by the Illinois language itself, in which the word for 'man' is ireniwa and plural 'men' is ireniwaki. The name Illiniwek has also been said to mean "tribe of superior men", though this is nothing more than a false etymology. In fact the name "Illinois" derives from the Miami-Illinois verb irenwe·wa "he speaks the regular way". This was then taken into the Ojibwe language, perhaps in the Ottawa dialect, and modified into ilinwe· (pluralized as ilinwe·k). These forms were then borrowed into French, where the /we/ ending acquired the spelling -ois. The current form, Illinois, began to appear in the early 1670s. The Illinois's name for themselves, as attested in all three of the French missionary-period dictionaries of Illinois, was Inoka, of unknown meaning and unrelated to the other terms.
 Boundaries
Illinois' eastern border with Indiana consists of a north-south line at 87° 31′ 30″ west longitude from Lake Michigan to the Wabash River above Post Vincennes. The Wabash River continues as the eastern/southeastern border with Indiana until the Wabash enters the Ohio River. This marks the beginning of Illinois' southern border with Kentucky, which runs along the northern shoreline of the Ohio River. Its western border with Missouri and Iowa is the Mississippi River. Its northern border with Wisconsin is fixed at 42° 30' north latitude. The northeastern border of Illinois actually lies within Lake Michigan, within which Illinois shares a water boundary with the state of Michigan.
 Urban areas
Chicago is the largest city in the state and the third most populous city in the United States, with its 2010 population of 2,695,598. The U.S. Census Bureau currently lists seven other cities with populations of over 100,000 within Illinois. Based upon the Census Bureau's official 2010 population,: Aurora, a Chicago satellite town which eclipsed Rockford for the title of "Second City" of Illinois in 2006; its 2010 population was 197,899. Rockford, at 152,871, is the third largest city in the state, and is also the largest city in the state not located within the Chicago metropolitan area. Joliet, located southwest of Chicago, is the fourth largest city in the state, with a population of 147,433. Naperville, a suburb of Chicago, is fifth with 141,853; Naperville and Aurora (the 2nd largest city) share a boundary along Illinois Route 59. Springfield, the state capital of Illinois, comes in sixth with 117,352. Peoria, which decades ago was the second largest city in the state, comes in seventh with 115,007. The eighth largest and final city in the 100,000 club is Elgin, a northwest suburb of Chicago with a 2010 population of 108,188.
The most populated city in the state south of Springfield is Belleville, with 44,478 people at the 2010 census. It is located in the Illinois portion of Greater St. Louis (often called the Metro-East area), which has a rapidly growing population of over 700,000 people.
Other major urban areas include the Champaign-Urbana Metropolitan Area, which has a combined population of almost 230,000 people, the Illinois portion of the Quad Cities area with about 215,000 people, and the Bloomington-Normal area with a combined population of over 165,000.
 Transportation
Because of its central location and its proximity to the Rust Belt and Grain Belt, Illinois is a national crossroads for air, auto, rail and truck traffic.
 Airports
From 1962 until 1998, Chicago's O'Hare International Airport (ORD) was the busiest airport in the world, measured both in terms of total flights and passengers. While it was surpassed by Atlanta's Hartsfield in 1998, with 59.3 million domestic passengers annually, along with 11.4 million international passengers in 2008, O'Hare remains one of the two or three busiest airports in the world, and some years still ranks number one in total flights. It is a major hub for United Airlines and American Airlines, and a major airport expansion project is currently underway. Chicago Midway International Airport (MDW), which had been the busiest airport in the world until supplanted by O'Hare in 1962, is now the secondary airport in the Chicago metropolitan area. For a time in the late 1960s and 1970s, Midway was nearly vacant except for general aviation, but growth in the area, combined with political deadlock over the building of a new major airport in the region, has caused a resurgence for Midway. It is now a major hub for Southwest Airlines, and services many other airlines as well. Midway served 17.3 million domestic and international passengers in 2008.
 Rail
Illinois has an extensive passenger and freight rail transportation network. Chicago is a national Amtrak hub and in-state passengers are served by Amtrak's Illinois Service, featuring the Chicago to Carbondale Illini and Saluki, the Chicago to Quincy Carl Sandburg and Illinois Zephyr, and the Chicago to St. Louis Lincoln Service. Currently there is trackwork on the Chicago-St. Louis line to bring the maximum speed up to 110 mph (180 km/h) which would reduce the trip time by an hour and a half. Nearly every North American railway meets at Chicago, making it the largest and most active rail hub in the country. Extensive commuter rail is provided in the city proper and some immediate suburbs by the Chicago Transit Authority's 'L' system. The largest suburban commuter rail system in the United States, operated by Metra, uses existing rail lines to provide direct commuter rail access for hundreds of suburbs to the city and beyond.
In addition to the state's rail lines, the Mississippi River and Illinois River provide major transportation routes for the state's agricultural interests. Lake Michigan gives Illinois access to the Atlantic Ocean by way of the Saint Lawrence Seaway.
 Interstate highway system
Illinois' central location and large population are the reasons that Illinois carries the distinction of having the most primary (2-digit) Interstates pass through it among the 50 states.
Major U.S. Interstate highways crossing the state include: I-24, I-39, I-55, I-57, I-64, I-70, I-72, I-74, I-80, I-88, I-90, and I-94.