The U.S. Census Bureau released more detailed 2010 Census population totals and demographic characteristics to the governor and leadership of the state legislature in Illinois. This data provides the first look at population counts for small areas and race, Hispanic origin, voting age and housing unit data released from the 2010 Census.
The official 2010 Census Redistricting Data Summary File can be used to redraw federal, state and local legislative districts under Public Law 94-171. The census data are used by state officials to realign congressional and state legislative districts in their states, taking into account population shifts since the 2000 Census.
Data for Illinois show that the five most populous incorporated places and their 2010 Census counts are Chicago, 2,695,598; Aurora, 197,899; Rockford, 152,871; Joliet, 147,433; and Naperville, 141,853. Chicago decreased by 6.9 percent since the 2000 Census. Aurora grew by 38.4 percent, Rockford grew by 1.8 percent, Joliet grew by 38.8 percent, and Naperville grew by 10.5 percent.
The largest county is Cook with a population of 5,194,675. Its population decreased by 3.4 percent since 2000. The other counties in the top five include DuPage, with a population of 916,924 (increase of 1.4 percent); Lake, 703,462 (increase of 9.2 percent); Will, 677,560 (increase of 34.9 percent); and Kane, 515,269 (increase of 27.5 percent).
The redistricting file consists of five detailed tables: the first shows the population by race, including six single race groups and 57 multiple race groups (63 total race categories); the second shows the Hispanic or Latino population as well as the non-Hispanic or Latino population cross-tabulated by the 63 race categories. These tabulations are repeated in the third and fourth tables for the population 18 years and over and are for the resident population of the United States. The fifth table provides counts of housing units and their occupancy status. These five detailed tables are available to the public online at http://factfinder2.census.gov