Illinois Flag

Illinois

Statehood Year:
1818
Capital:
Springfield
Largest Cities:
Chicago, Aurora, Naperville
Abbreviation:
IL

Illinois is a state in the Midwest region of the United States, known for the Great Lakes shoreline, prairie lands, and urban Chicago. It has a population of 12,778,100, making it the 6th most populated state in the country. The capital city is Springfield. Illinois has a diverse economy with financial services and manufacturing strength.

12,778,100
Total Population
221
Population Density (mi²)
6
Population Rank
67.9K 0.53%
Annual Population Growth

Illinois Population

Demographics

Economics and Income Statistics

Population by County

Population by County

2025 Pop.

500K

1M

1.5M

2M

2.5M

3M

3.5M

4M

4.5M

5M

Population Growth by County

Change (2020)

-0.05

-0.025

0

0.025

0.05

0.075

Population Density by County

Density

500

1000

1.5K

2K

2.5K

3K

3.5K

4K

4.5K

5K

5.5K

Sources

  1. US Census State Population Estimates - Most recent state estimates from the Census Bureau's Population Estimates Program
  2. US Census County Population Estimates - Most recent county estimates from the Census Bureau's Population Estimates Program
  3. American Community Survey (2009 - 2013)
  4. Census QuickFacts
  5. Historical Populations of States and Counties (1790 - 1990)