Share of the population by age and sex, five-year groups

Population of Illinois, 2010–2025 · click to pick a year
Estimates up to 2019 are built on the 2010 Census, those from 2020 on the 2020 Census. A line that steps up or down between 2019 and 2020 reflects this re-basing, not a sudden change in population.

Year

-5 -1   2015  +1 +5

12,859,585 people lived in Illinois on July 1, 2015: the 5th-largest population among the 50 states and the District of Columbia. The median age was 37.6 years (United States: 37.8); children under 15 (19.0%) clearly outnumber residents 65 and older (14.3%): a relatively young population. There were 96.5 men for every 100 women. Since 2010 the population has grown by 0.1%. Source: U.S. Census Bureau, Population Estimates Program, Vintage 2020 estimates (resident population on July 1; public domain). Median age, shares, dependency ratios and rankings are calculated by PopulationPyramid.net from these estimates; the Census Bureau does not endorse this site.

Key indicators, 2015
Population
12,859,585
Rank by population
5th of 51
Median age
37.6
Men per 100 women
96.5
Under 15
19.0%
15–64
66.6%
65 and over
14.3%
Child dependency
28.6
Old-age dependency
21.5
Change since 2010
+0.1%
Dependency ratios count children under 15 or adults 65 and over per 100 residents aged 15 to 64.
Show the population by age group, 2015
AgeMenWomenTotalShare
0-4402,219384,437786,6566.1%
5-9416,749401,623818,3726.4%
10-14429,845411,801841,6466.5%
15-19435,953415,871851,8246.6%
20-24456,972441,508898,4807.0%
25-29453,693442,297895,9907.0%
30-34445,615443,022888,6376.9%
35-39419,914419,184839,0986.5%
40-44407,462412,642820,1046.4%
45-49415,102422,831837,9336.5%
50-54441,307456,540897,8477.0%
55-59429,883453,196883,0796.9%
60-64362,673393,325755,9985.9%
65-69287,695323,481611,1764.8%
70-74196,732236,610433,3423.4%
75-79135,117177,034312,1512.4%
80-8491,158135,124226,2821.8%
85+86,000174,970260,9702.0%
How Illinois compares with similar-sized states, 2015
RankStateResidentsRelative
2 Texas 27,468,531
3 Florida 20,219,111
4 New York 19,657,321
5 Illinois 12,859,585
6 Pennsylvania 12,789,838
7 Ohio 11,622,315
8 Georgia 10,183,353
Frequently asked questions about Illinois's population
What is the population of Illinois?
Illinois had an estimated 12,859,585 residents on July 1, 2015, according to the U.S. Census Bureau, Population Estimates Program. That ranks 5th among the 51 states and the District of Columbia.
What is the median age in Illinois?
The median age in Illinois was 37.6 years in 2015, the 32nd oldest of the 51 states and DC. That is 0.2 years younger than the national median of 37.8.
How many people in Illinois are 65 or older?
About 1,843,921 residents of Illinois (14.3%) were 65 or older in 2015, against 19.0% under 15 and 66.6% aged 15 to 64.
What does the population pyramid of Illinois show?
In 2015, Illinois: children under 15 (19.0%) clearly outnumber residents 65 and older (14.3%): a relatively young population. There were 96.5 men for every 100 women.
How fast is the population of Illinois changing?
The population of Illinois grew by 0.1% between 2010 and 2015, and by -0.2% in the last year.
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