Illinois Population 2020
The 2015 Census estimates put the population at 12,859,995, which was a decrease from the 2014 numbers. Illinois is one of only 7 states that has a negative growth rate in 2016. At -0.17% per year, it is ahead of only West Virginia. Between 2000 and 2010, the population of Illinois grew by a mere 3.3%, compared to the national average US population growth of 9.7%.
The 2018 population estimates Illinois is the sixth largest state in the USA based on population.
Illinois Surface Area and Population Density
The total area of Illinois is 57,914 square miles, with a population density of 230 people per square mile.
Most of the Illinois population is heavily concentrated in the North East of the state in the metropolitan area of Chicago. Chicago, which is home to 2,720,546 people, remains the largest city in Illinois. This city dwarfs the state's other cities, including the capital of the state. The next largest is Aurora, with 200,661 people.
This marks one of Illinois' defining features -- although it has a large urban population, it is spread through a number of smaller cities. Including Chicago, there are twelve cities (including the city of Springfield, the state's capital) with more than 75,000 people.
Many of these smaller cities make up a part of the Chicago Metropolitan Area (prosaically also known as Chicagoland), which holds between 8.3 and 9.8 million people, depending on how you classify its boundaries.
Cook County is the largest county in Illinois, housing 5,238,216 people. The next largest county is neighboring Dupage, with 933,736 people. Almost half of the Illinois population can be found in just those two counties.
Illinois Gender and Religion Statistics
The median age in Illinois is 37.4 years of age, with a slight gender difference over the state- 50.9% female and 49.1% male.
In religious terms, Illinois shows its preferences with a 71% preference for Christian based faiths, a 6% affiliation with non-Christian based faiths, and 22% of the population being unaffiliated with any particular religion.
Illinois Boundary, Census, and Statehood History
Illinois was included in the Northwest Territory established in 1787 and then in Indiana Territory (1800). Illinois Territory was established in 1809, and included virtually all of present-day Wisconsin and portions of Minnesota and the Upper Peninsula of Michigan. Illinois was admitted as a State on December 3, 1818 with essentially its present boundaries.
In 1790 the Northwest Territory had no census coverage. The population shown for 1800 is the total of two counties and one community in present-day Illinois, at that time part of Indiana Territory. Knox County, Indiana Territory, also included some population in what is now Illinois. In 1810, the returns for the two counties of Illinois Territory included some settlements in present-day Wisconsin. The northern part of the State was not fully covered by the census until 1830.
Illinois Demographics
According to the most recent ACS, the racial composition of Illinois was:
Illinois Population History
Illinois saw massive growth throughout the 19th century, from a measly 2,458 people in 1800 to nearly 5 million in 1900. This rise made Illinois the 3rd largest state by the turn of the century. Growth continued into the 20th century, albeit at a slower pace.
Illinois Population Growth
In Illinois' cities, population growth has stalled. Chicago was, for much of its early history, one of America's fastest growing cities. Between 1850 and 1930, the city grew by at least 25% each decade, and in some decades it doubled or even tripled in size. However, from the 1960s onwards, Chicago has been steadily shrinking and a city which was home to 3.5 million people in 1960 is home to just 2.7 million today.
Illinois Population Projections
If the current decline continues, Illinois will fall back to the 6th spot in state rankings at the 2020 Census, behind Pennsylvania.
Some estimates expect Illinois to see growth again by 2020, and possibly reach 13.1 million in 2020.
Based on data from the 2010 Census, Illinois has the 14th highest percentage of African Americans across all states. Based on 2011 data, the state also has the 5th highest Hispanic population in the country with over 2 million Hispanic residents, and the 10th highest percentage of Hispanics that account for its diverse total population.
In recent years, Illinois has seen significant declines in its white population, with numbers dropping from 83.5% of the total population in 1970 to 63.3% just 40 years later. According to 2011 data, almost 50% of the population under the age of 1 were minorities.
According to data from 2007, over 1.7 million people in Illinois were foreign-born. This represented, at the time, almost 14% of the population. Over 48% of Illinois' foreign-born inhabitants came from Latin America, while almost one-quarter of the total number came from Asia. It is estimated that over 58% of the total 1.7 million foreign-born inhabitants recorded were not US citizens.
2020 Population Rank
Illinois Square Miles
57,914 (25)
State Capital
Statehood Year
Cities in Illinois
Counties in Illinois
Zip Codes in Illinois
Where is Illinois?
Illinois Growth Rate
Illinois Population Rank
Illinois Flag
Illinois has the world's only river that flows backwards.
Chicago's Lincoln Park Zoo is the country's fourth oldest public zoo.
Almost 80% of the land in Illinois is farmland.
The Sears Tower (aka Willis Tower), located in Chicago, is the tallest building in North America.
In 1865, Illinois ratified the 13th Amendment to abolish slavery. It was the first state to do so.
There are 102 counties in the state of Illinois.
The country's 9th largest public library is the Chicago Public Library, which houses over 5 million books.
Illinois has more units of government than any other state.
The oldest community in Illinois is Peoria.
Illinois Facts
Population5,128,510
Density5425.09 per sq km
Growth Since 2010-1.36%
State Population Rank1
% of State40.64%
When looking at population growth of the state of Illinois by county, the data show that the majority of counties have seen population declines. However, there were still a handful of counties that saw small rates of growth, based on data taken from the 2010 Census and again during 2015 estimates taken by the US Census Bureau. During this 5-year period, Kendall County exhibited the most growth at a rate of 6.98%. Other counties that saw growth during this time period include Kane County at 2.86%, Champaign at 3.66%, and Monroe at 2.63%.
There were far more counties that experienced declines in population. This includes Alexander County, which by far had the biggest decline percentage at over 17%. Other counties with declining populations include Mason at 6.49%, Livingston at 5.66%, and Cass at 5.77%, among others.
Illinois Population Growth Rate by County
Illinois Population Density by County
White 9,134,900 71.53%
Black or African American 1,813,592 14.20%
Some Other Race 757,231 5.93%
Asian 698,524 5.47%
Two or More Races 328,446 2.57%
American Indian and Alaska Native 33,460 0.26%
Native Hawaiian and Other Pacific Islander 4,477 0.04%
Illinois Population by Race
Illinois Population Pyramid 2020
Illinois Median Age
Illinois Adults
There are 9,879,100 adults, (1,942,530 of whom are seniors) in Illinois.
Illinois Age Dependency
Illinois Sex Ratio
Illinois Population by Age
Illinois Renter vs Owner Occupied by Household Type
Illinois Household Types
Illinois Households and Families
All 4,846,130 2.57 66.1
Married 2,295,460 3.27 83.3
Non Family 1,736,370 1.25 50.6
Female 591,628 3.44 47.6
Male 222,678 3.42 58.3
Illinois Households by Type
Less Than 9th Grade 419,259 4.83%
9th to 12th Grade 517,783 5.96%
High School Graduate 2,254,520 25.95%
Some College 1,784,180 20.54%
Associates Degree 700,533 8.06%
Bachelors Degree 1,831,440 21.08%
Graduate Degree 1,178,590 13.57%
Illinois Educational Attainment by Sex (over 25)
Illinois Educational Attainment by Race
White 5,706,930 5,375,280 2,214,180
Hispanic 1,218,060 824,178 181,772
Black 1,165,510 1,008,390 252,398
Asian 492,177 446,395 319,207
Other Race 431,849 265,395 44,767
Multiple Races 130,813 117,343 49,471
Native American 22,294 16,686 4,295
Islander 2,850 2,496 939
The highest rate of bachelors degrees is among asian people with a rate of 64.86%.
Illinois Earnings by Educational Attainment
Illinois Language by Age
Illinois Language
76.84% of Illinois residents speak only English, while 23.16% speak other languages. The non-English language spoken by the largest group is Spanish, which is spoken by 13.51% of the population.
Illinois Poverty by Race
White 7,665,980 647,632 8.45%
Black 1,736,570 453,271 26.10%
Hispanic 2,150,590 345,198 16.05%
Other 751,579 131,250 17.46%
Asian 685,046 74,314 10.85%
Multiple 320,825 51,187 15.95%
Native 32,478 5,327 16.40%
Islander 4,336 547 12.62%
Poverty in Illinois
The race most likely to be in poverty in Illinois is Black, with 26.10% below the poverty level.
The race least likely to be in poverty in Illinois is White, with 8.45% below the poverty level.
Illinois Poverty
Illinois Poverty Rate by Education
Illinois Poverty Rate by Employment Status and Sex
Illinois Income by Household Type
Families $83,279 $110,401
Married Families $99,963 $128,878
Illinois Marital Status
Illinois Married by Age and Sex
Illinois Marriage
Illinois Marital Status by Race
First Gulf War 97,457
Second Gulf War 88,921
Korea 51,593
World War II 23,658
Illinois Veterans by War
65 to 74 161,876
75+ 148,301
55 to 64 90,662
Illinois Veterans by Age
White 472,326 6.54%
Black 74,220 5.44%
Hispanic 29,366 2.00%
2 or More 8,909 5.26%
Other 6,582 1.26%
Indian 1,409 5.49%
Hawaiian 235 6.90%
Illinois Veterans by Race
Illinois Veterans by Education
Illinois Employment by Age
Illinois Employment by Race
Illinois Employment by Education
Born in Illinois
85.93% of Illinois residents were born in the United States, with 67.08% having been born in Illinois. 6.94% of residents are not US citizens. Of those not born in the United States, the largest percentage are from Latin America.
Illinois Place of Birth