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 not only the number three city, it also remains 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, it shares its western border with the state's second largest city, Aurora, 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.