St. Clair County, Illinois Population 2021

St. Clair County, Illinois's estimated population is 256,338 with a growth rate of -0.65% in the past year according to the most recent United States census data. St. Clair County, Illinois is the 10th largest county in Illinois. The 2010 Population was 270,353 and has seen a growth of -5.18% since this time.

Note: 2020 and 2021 data is projected
Year Population Growth Growth Rate
2021256,338-1,674-0.65%
2020258,012-1,674-0.64%
2019259,686-1,674-0.64%
2018261,360-1,240-0.47%
2017262,600-587-0.22%
2016263,187-1,671-0.63%
2015264,858-1,083-0.41%
2014265,941-890-0.33%
2013266,831-1,842-0.69%
2012268,673-1,375-0.51%
2011270,048-305-0.11%
2010270,3537,5012.85%
1990262,852-4,679-1.75%
1980267,531-17,645-6.19%
1970285,17622,6678.63%
1960262,50956,51427.43%
1950205,99539,09623.42%
1940166,8999,1245.78%
1930157,77521,25515.57%
1920136,52016,65013.89%
1910119,87033,18538.28%
190086,68520,11430.21%
189066,5714,7657.71%
188061,80610,73821.03%
187051,06813,37435.48%
186037,69417,51486.79%
185020,1806,54948.04%
184013,6316,55392.58%
18307,0781,82534.74%
18205,2532464.91%
18105,0073,652269.52%
18001,3550.00%
2021 Growth Rate
-0.65%
County Website
Founded
1790
County Seat
2010 Population
270,353
Growth Since 2010
-5.18%
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St. Clair County, Illinois Population Growth

Population by Race

Race Population Percentage
White168,09664.08%
Black or African American78,53229.94%
Two or More Races7,7882.97%
Asian3,8611.47%
Some Other Race3,4021.30%
American Indian and Alaska Native5900.22%
Native Hawaiian and Other Pacific Islander690.03%
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St. Clair County, Illinois Population by Race

St. Clair County, Illinois Population Pyramid $2021

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St. Clair County, Illinois Median Age

38.6


Total

36.8


Male

40.2


Female

St. Clair County, Illinois Adults

There are 200,499 adults, (39,961 of whom are seniors) in St. Clair County, Illinois.

St. Clair County, Illinois Age Dependency

63.4

Age Dependency Ratio

24.9

Old Age Dependency Ratio

38.5

Child Dependency Ratio

St. Clair County, Illinois Sex Ratio

Female

135,604

51.69%

Male

126,734

48.31%

St. Clair County, Illinois Population by Age

St. Clair County, Illinois Renter vs Owner Occupied by Household Type

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St. Clair County, Illinois Household Types

Type Owner Renter
Married84.6%15.4%
Male67.8%32.2%
All65.2%34.8%
Non Family52%48%
Female41.2%58.8%

65.2%

Rate of Home Ownership

St. Clair County, Illinois Households and Families

Type Count Average Size Owned
All104,1052.4865.2
Married44,6643.1584.6
Non Family38,9381.1752
Female15,2973.6441.2
Male5,2063.2367.8

3.18

Average Family Size

2.48

Average Household Size

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St. Clair County, Illinois Households by Type

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Education Attained Count Percentage
Less Than 9th Grade4,5212.54%
9th to 12th Grade11,4376.41%
High School Graduate50,18728.14%
Some College42,85224.03%
Associates Degree19,38310.87%
Bachelors Degree29,26116.41%
Graduate Degree20,69311.60%
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St. Clair County, Illinois Educational Attainment by Sex (over 25)

St. Clair County, Illinois Educational Attainment by Race

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Race Total High School Bachelors
White118,007111,01938,068
Black49,03441,8738,319
Hispanic5,7214,3571,379
2+ Races2,7582,630819
Asian2,7312,3841,367
Other Race2,0111,313380
Native American43939363
Islander60608

The highest rate of high school graduation is among islander people with a rate of 100.00%.

The highest rate of bachelors degrees is among asian people with a rate of 50.05%.

St. Clair County, Illinois Educational Attainment by Race

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Name Average Male Female
Overall$39,280$46,424$31,839
Less Than 9th Grade$21,317$23,326$17,154
High School Graduate$29,682$35,103$23,104
Some College$36,523$44,639$29,548
Bachelors Degree$55,136$69,688$43,004
Graduate Degree$66,516$86,705$54,607

$39,280

Average Earnings

$46,424

Average Male

$31,839

Average Female

St. Clair County, Illinois Earnings by Educational Attainment

St. Clair County, Illinois Language by Age

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St. Clair County, Illinois Language

94.33% of St. Clair County, Illinois residents speak only English, while 5.67% speak other languages. The non-English language spoken by the largest group is Spanish, which is spoken by 2.67% of the population.

St. Clair County, Illinois Language

St. Clair County, Illinois Poverty by Race

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Name Total In Poverty Poverty Rate
Black77,27223,06929.85%
White159,08511,3477.13%
Hispanic10,4942,30221.94%
Multiple7,6111,22116.04%
Other3,3961,17334.54%
Asian3,8112316.06%
Native59013723.22%
Islander69811.59%

14.76%

Overall Poverty Rate

12.88%

Male Poverty Rate

16.50%

Female Poverty Rate

Poverty in St. Clair County, Illinois

The race most likely to be in poverty in St. Clair County, Illinois is Other, with 34.54% below the poverty level.

The race least likely to be in poverty in St. Clair County, Illinois is Asian, with 6.06% below the poverty level.

The poverty rate among those that worked full-time for the past 12 months was 2.84%. Among those working part-time, it was 17.07%, and for those that did not work, the poverty rate was 22.24%.

St. Clair County, Illinois Poverty

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Name Poverty
Less Than 9th Grade29.60%
High School14.92%
Some College10.36%
Bachelors or Greater4.10%

St. Clair County, Illinois Poverty Rate by Education

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Rate Poverty
Female Unemployed38.16%
Male Unemployed29.74%
Female Employed9.70%
Male Employed4.21%

St. Clair County, Illinois Poverty Rate by Employment Status and Sex

St. Clair County, Illinois Income by Household Type

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Name Median Mean
Households$55,179$75,474
Families$75,024$93,092
Married Families$93,956$113,957
Non Families$31,034$42,856
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Income by Household Type

St. Clair County, Illinois Marital Status

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Marriage Rates

45.5%

Overall Marriage Rate

47.9%

Male Marriage Rate

43.3%

Female Marriage Rate

St. Clair County, Illinois Married by Age and Sex

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St. Clair County, Illinois Marriage

The age group where males are most likely to be married is Over 65, while the female age group most likely to be married is 45-54.

St. Clair County, Illinois Marital Status by Race

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St. Clair County, Illinois Marital Status

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24,608

Number of Veterans

21,403

Male Veterans

3,205

Female Veterans

War Veterans
First Gulf War8,933
Vietnam7,904
Second Gulf War7,162
Korea1,232
World War II687

St. Clair County, Illinois Veterans by War

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Age Group Veterans
35 to 547,498
65 to 745,651
55 to 645,567
75+3,718
18 to 342,174

St. Clair County, Illinois Veterans by Age

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Name Veterans % of Total
White18,23413.93%
Black5,1939.17%
Hispanic67110.18%
2+ Races64518.50%
Other Race24610.93%
Asian1846.06%
Native American9818.81%
Islander811.76%

St. Clair County, Illinois Veterans by Race

St. Clair County, Illinois Veterans by Education

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6.43%

Veteran Poverty Rate

23.57%

Veteran Disability Rate

St. Clair County, Illinois Veterans by Education

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64.2%

Labor Force Participation

58.3%

Employment Rate

6.7%

Unemployment Rate

St. Clair County, Illinois Employment by Age

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St. Clair County, Illinois Employment by Race

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St. Clair County, Illinois Employment by Education

Origin of Non-Citizens

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Non citizens include legal permanent residents (green card holders), international students, temporary workers, humanitarian migrants, and illegal immigrants.

Origin of Naturalized Citizens

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58.98%

Born in St. Clair County, Illinois

96.87%

Native Born

3.13%

Foreign Born

1.63%

Non Citizen

1.49%

Naturalized

Place of Birth

96.87% of St. Clair County, Illinois residents were born in the United States, with 58.98% having been born in Illinois. 1.63% of residents are not US citizens. Of those not born in the United States, the largest percentage are from Asia.

St. Clair County, Illinois Place of Birth

  1. US Census City/Town Population estimates - Most recent state estimates from the Census Bureau's Population Estimates Program
  2. Population of States and Counties of the United States: 1790 - 1990

Sources