Illinois Population 2018

12,768,320

The population of Illinois in 2018 is estimated at 12.77 million. 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 makes Illinois 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 Demographics

Age/Sex, Race, Religion

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.

The racial diversity of Illinois is shown below in a chart, and we can see that 72.1% of the population is Caucasian, 14.3% African American, 5.9% other races, 5.1% Asian, 2.3% two or more, and 0% Natives of America/Alaska/Islanders.

In religious terms, Illnois 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 Population Chart

Illinois Population History

Illinois saw massive growth throughout the 19th century, from a measley 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.

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.

Population Data via US Census

Illinois Growth Rate

Illinois Population Rank

Year Pop % Change
202012,700,914-0.26%
201912,734,617-0.26%
201812,768,320-0.26%
201712,802,023-0.26%
201612,835,726-0.20%
201512,862,051-0.16%
201412,882,438-0.06%
201312,890,4030.09%
201212,878,4940.13%
201112,862,2980.16%
201012,841,1960.33%
200012,419,2930.83%
199011,430,6020.00%
198011,426,5180.28%
197011,113,9760.98%
196010,081,1581.47%
19508,712,1760.99%
19407,897,2410.34%
19307,630,6541.64%
19206,485,2801.41%
19105,638,5911.58%
19004,821,5502.34%
18903,826,3512.20%
18803,077,8711.94%
18702,539,8914.02%
18601,711,9517.23%
1850851,4705.98%
1840476,18311.70%
1830157,44511.05%
182055,21116.22%
181012,28217.45%
18002,4580.00%

Illinois Facts

Illinois Population in 2018Source: By Adrian104 [Public domain], from Wikimedia Commons

Illinois Population Density by County

Cook County

  • Population5,211,263
  • Density5512.62 per sq km
  • Growth Since 20100.23%
  • State Rank1
  • % of State40.71%

Illinois Population Growth Rate by County

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%, Livinsgton at 5.66%, and Cass at 5.77%, among others.

Population by Race

Race Population
White9,236,701
Black or African American1,833,501
Some Other Race767,145
Asian671,811
Two or More Races311,397
American Indian and Alaska Native29,696
Native Hawaiian and Other Pacific Islander4,275

Data via US Census (2017 ACS 5-Year Survey): Table B03002

Illinois Population Pyramid 2018

100,000200,000300,000400,000500,000 Male Population100,000200,000300,000400,000500,000 Female Population80757065605550454035302520151050

Data via US Census (2017 ACS 5-Year Survey): Table S0101

Illinois Median Age

37.7


Total

36.4


Male

38.9


Female

Illinois Adults

There are 9,895,529 adults, (1,847,932 of whom are seniors) in Illinois.

Illinois Age Dependency

59.7

Age Dependency Ratio

23

Old Age Dependency Ratio

36.8

Child Dependency Ratio

Illinois Sex Ratio

Female

6,541,926

50.89%

Male

6,312,600

49.11%

Illinois Households and Families

Illinois Renter vs Owner Occupied by Household Type

Data via US Census (2017 ACS 5-Year Survey): Table S1101

Illinois Household Types

Type Owner Renter
Married83%17%
All66.1%33.9%
Male57.2%42.8%
Non Family50.9%49.1%
Female47.4%52.6%

66.1%

Rate of Home Ownership

Illinois Households by Type

Type Count Average Size Owned
All4,818,4522.6166.1
Married2,303,7753.2983
Non Family1,695,9611.2550.9
Female597,4593.4847.4
Male221,2573.4857.2

3.26

Average Family Size

2.61

Average Household Size

5.4%

Unmarried (Opposite Sex)

0.3%

Unmarried (Same Sex)

Illinois Households

Illinois Education

Illinois Educational Attainment by Sex (over 25)

Education Attained Count Percentage
Less Than 9th Grade446,6255.15%
9th to 12th Grade544,7996.29%
High School Graduate2,281,52426.33%
Some College1,812,24720.91%
Associates Degree682,3007.87%
Bachelors Degree1,776,32620.50%
Graduate Degree1,122,25812.95%

Illinois Educational Attainment by Race

Name Total High School Bachelors
White5,760,7485,399,1642,154,469
Hispanic1,186,705771,320165,485
Black1,153,163988,713240,188
Asian469,283426,592300,448
Other Race430,124250,79441,760
Multiple Races119,262105,92942,993
Native American20,18315,5703,907
Islander2,8472,476746

The highest rate of high school graduation is among white people with a rate of 93.72%.

The highest rate of bachelors degrees is among white people with a rate of 64.02%.

Illinois Earnings by Educational Attainment

Name Average Male Female
Overall$40,648$48,455$32,982
Less Than High School$22,796$26,783$17,705
High School Grad$30,506$36,559$23,513
Some College$36,046$45,162$29,479
Bachelors Degree$54,646$67,711$45,112
Graduate Degree$72,270$90,816$60,986

$40,648

Average Earnings

$48,455

Average Male

$32,982

Average Female

Illinois Language

Illinois Language by Age

Illinois Language

77.16% of Illinois residents speak only English, while 22.84% speak other languages. The largest non-English language is Spanish, which is spoken by 13.33% of the population.

Illinois Poverty

Illinois Poverty by Race

Name Total In Poverty Poverty Rate
White7,787,654695,4658.93%
Black1,754,135502,01428.62%
Hispanic2,126,247388,43418.27%
Other760,043149,70519.70%
Asian658,61275,01811.39%
Multiple302,74853,35517.62%
Native29,0285,73619.76%
Islander4,06650112.32%

13.53%

Overall Poverty Rate

12.25%

Male Poverty Rate

14.76%

Female Poverty Rate

Poverty in Illinois

The race most likely to be in poverty in Illinois is Black, with 28.62% below the poverty level.

The race least likely to be in poverty in Illinois is White, with 8.93% below the poverty level.

The poverty rate among those that worked full-time for the past 12 months was 2.43%. Among those working part-time, it was 16.07%, and for those that did not work, the poverty rate was 21.99%.

Illinois Poverty Rate by Education

Name Poverty
Less Than High School23.44%
High School13.69%
Some College10.02%
Bachelors or Greater4.44%

Illinois Poverty Rate by Employment Status and Sex

Name Poverty
Female Unemployed36.43%
Male Unemployed29.31%
Female Employed7.48%
Male Employed5.05%

Illinois Income

Illinois Income by Household Type

Name Median Mean
Households$61,229$85,262
Families$76,533$101,360
Married Families$91,973$118,479
Non Families$36,233$52,753

Illinois Marital Status

Illinois Marital Status

Marriage Rates

47.8%

Overall Marriage Rate

49.6%

Male Marriage Rate

46.1%

Female Marriage Rate

Illinois Married by Age and Sex

Illinois Marriage

The age group where males are most likely to be married is Over65, while the female age group most likely to be married is 45To54.

Illinois Marital Status by Race


Data via US Census (2017 ACS 5-Year Survey): Table S1201

Illinois Veterans

Illinois Veterans by War

614,725

Number of Veterans

572,866

Male Veterans

41,859

Female Veterans

Name Veterans
Vietnam222,045
First Gulf War98,545
Second Gulf War80,360
Korea65,207
World War II36,583

Illinois Veterans by Age

Name Veterans
65 to 74168,516
75+158,832
35 to 54134,292
55 to 64104,965
18 to 3448,120

Illinois Veterans by Race

Name Veterans % of Total
White510,2807.02%
Black80,2465.88%
Hispanic27,9141.94%
2 or More9,0215.72%
Other7,1471.37%
Asian6,2411.17%
Indian1,4996.51%
Hawaiian2918.59%

Illinois Veterans by Education

7.07%

Veteran Poverty Rate

27.61%

Veteran Disability Rate

Illinois Employment Status

Illinois Employment by Age

65.3%

Labor Force Participation

60.4%

Employment Rate

7.4%

Unemployment Rate

Illinois Employment by Race

Illinois Employment by Education

Illinois Nativity

Illinois Citizenship Status

Data 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)