On February 15, 2011, the U.S. Census Bureau released redistricting data for the State of Illinois. This includes data on population, racial, ethnic, and housing characteristics for geographies ranging from counties to census tracts. The data show that the Chicago metropolitan area grew from 8.2 million to 8.4 million residents between April 1, 2000 and April 1, 2010, an increase of 3.6 percent.

The seven-county metropolitan Chicago region made up 66 percent of the state's population in both 2000 and 2010. While the region grew along with the state, certain areas of northeastern Illinois experienced declines in population. Cook County's population declined by 182,066 residents, and the collar counties (DuPage, Kane, Kendall, Lake, McHenry, and Will counties) gained an additional 467,188 resident over the ten-year period. Kendall continues to have the smallest county population in the region, though its population increased by 110.4 percent to 114,736 residents. Over the ten-year period, Kendall's population growth rate was higher than any other county in the State.

The City of Chicago's population dropped over the ten-year period from 2.9 million to 2.7 million residents. Chicago's residents made up 31.9 percent of the region's population in 2010, down from 35.5 percent of the region's population in 2000. CMAP will continue to analyze the data in the coming months, and the latest data for northeastern Illinois is available for download at www.cmap.illinois.gov/2010-census. The U.S. Census website also features interactive state maps with the latest data release.