Population 253,694 · Census ACS 2020–24
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Population and households in St. Clair County
Household size in St. Clair County
| Period | St. Clair County | St. Louis area | Illinois | U.S. |
|---|---|---|---|---|
| 2006–10 | 2.59 | 2.52 | 2.69 | 2.68 |
| 2010–14 | 2.63 | 2.53 | 2.71 | 2.73 |
| 2015–19 | 2.53 | 2.49 | 2.66 | 2.71 |
| 2020–24 | 2.57 | 2.46 | 2.58 | 2.65 |
| Change | −0.03 | −0.06 | −0.11 | −0.03 |
The average household in St. Clair County has 2.57 people, a bit under the U.S. average of 2.65. Even so, the typical household here is bigger than in the St. Louis area overall, where it has 2.46 people. Households are largest in the west and smallest in the center.
Household size: the average number of people living in each occupied home. Source: BestNeighborhood calculations from U.S. Census Bureau ACS 5-year block-group estimates (table B25010).
Median age in St. Clair County
| Period | St. Clair County | St. Louis area | Illinois | U.S. |
|---|---|---|---|---|
| 2006–10 | 37.7 | 38.5 | 37.6 | 37.7 |
| 2010–14 | 38.7 | 39.5 | 38.5 | 38.6 |
| 2015–19 | 40.1 | 40.7 | 39.6 | 39.6 |
| 2020–24 | 40.2 | 40.8 | 40.2 | 40.1 |
| Change | +2.5 | +2.3 | +2.6 | +2.3 |
At 40.2, the median age in St. Clair County is close to the national median of 40.1, so its age mix looks much like the country's. The median age has climbed from 37.7 in 2006–10, in line with the national trend. St. Clair County is younger than the great majority of Illinois counties.
Median age: the age that splits residents into two equal halves. Source: BestNeighborhood calculations from U.S. Census Bureau ACS 5-year block-group estimates (table B01002).
Single-parent households in St. Clair County
| Period | St. Clair County | St. Louis area | Illinois | U.S. |
|---|---|---|---|---|
| 2006–10 | 15.0% | 11.7% | 11.7% | 12.3% |
| 2010–14 | 13.9% | 11.5% | 11.7% | 12.3% |
| 2015–19 | 12.6% | 11.0% | 11.1% | 11.6% |
| 2020–24 | 13.5% | 11.1% | 11.3% | 11.6% |
| Change | −1.4 pts | −0.6 pts | −0.4 pts | −0.6 pts |
Single parents head nearly one in seven households in St. Clair County (13.5%), a bit above the national share of 11.6%. Since 2006–10, the single-parent share has edged down 1.4 points, mirroring the country. Few Illinois counties have a higher share of single-parent households: only five of 102.
Single-parent households: households where one adult with no spouse present lives with children under 18. Source: BestNeighborhood calculations from U.S. Census Bureau ACS 5-year block-group estimates (table B11003).
Housing in St. Clair County
Renters in St. Clair County
| Period | St. Clair County | St. Louis area | Illinois | U.S. |
|---|---|---|---|---|
| 2006–10 | 32.3% | 28.3% | 30.8% | 33.3% |
| 2010–14 | 33.5% | 30.1% | 33.1% | 35.6% |
| 2015–19 | 34.8% | 31.1% | 33.9% | 36.0% |
| 2020–24 | 31.6% | 29.6% | 32.9% | 34.8% |
| Change | −0.7 pts | +1.4 pts | +2.1 pts | +1.5 pts |
Just over three in ten households in St. Clair County rent their homes (31.6%), a little below the national share of 34.8%; the rest own. Just over four in ten owners (41.9%) have paid off their mortgages, about the same as nationally. The renter share is down 0.7 points from 2006–10, even as the national share rose.
Renters: occupied homes that are rented rather than owned. Source: BestNeighborhood calculations from U.S. Census Bureau ACS 5-year block-group estimates (table B25003).
Vacant homes in St. Clair County
| Period | St. Clair County | St. Louis area | Illinois | U.S. |
|---|---|---|---|---|
| 2006–10 | 10.3% | 9.6% | 10.0% | 11.4% |
| 2010–14 | 12.2% | 10.1% | 10.1% | 11.4% |
| 2015–19 | 13.0% | 10.1% | 9.8% | 11.1% |
| 2020–24 | 11.5% | 8.8% | 8.1% | 9.6% |
| Change | +1.1 pts | −0.8 pts | −1.9 pts | −1.8 pts |
Vacancy runs a little high in St. Clair County: 11.5% of homes are empty, against 9.6% nationally. The count includes vacation homes and homes between owners or tenants, not just abandoned ones. Since 2006–10, vacancy has edged up 1.1 points, even as the national rate fell.
Vacant homes: homes with no one living in them, including vacation homes and homes for sale or rent. Source: BestNeighborhood calculations from U.S. Census Bureau ACS 5-year block-group estimates (table B25002).
Age of homes in St. Clair County
| Period | St. Clair County | St. Louis area | Illinois | U.S. |
|---|---|---|---|---|
| 2006–10 | 1974 | 1972 | 1966 | 1974 |
| 2010–14 | 1976 | 1972 | 1967 | 1975 |
| 2015–19 | 1976 | 1973 | 1968 | 1977 |
| 2020–24 | 1978 | 1975 | 1970 | 1980 |
| Change | +4 | +3 | +4 | +6 |
The typical home in St. Clair County was built around 1978, about the same vintage as the country's housing overall (1980). The median year built has moved up from 1974 in 2006–10, a sign of steady new building. Newer construction is concentrated in the east, while the northwest has the oldest housing.
Age of homes: the year that splits the housing stock into older and newer halves. Source: BestNeighborhood calculations from U.S. Census Bureau ACS 5-year block-group estimates (table B25035).
Rent in St. Clair County
| Period | St. Clair County | St. Louis area | Illinois | U.S. |
|---|---|---|---|---|
| 2006–10 | $814 | $825 | $953 | $965 |
| 2010–14 | $912 | $920 | $1,028 | $1,040 |
| 2015–19 | $997 | $1,010 | $1,165 | $1,213 |
| 2020–24 | $1,199 | $1,239 | $1,428 | $1,571 |
| Change | +$385 | +$414 | +$475 | +$606 |
Rent in St. Clair County runs $1,199 a month at the median, utilities included, well below the U.S. median of $1,571. Rents are up $385 a month from 2006–10, a 47% rise, a slower climb than the nation's. The typical renter here spends 29.8% of household income on rent, just under the 30% mark often used to define affordable rent, and a smaller share than renters pay nationally. Rents run highest in the northeast and lowest in the northwest.
Rent: monthly rent plus the utilities renters pay themselves. Source: BestNeighborhood calculations from U.S. Census Bureau ACS 5-year block-group estimates (table B25064).
Education in St. Clair County
Bachelor's degrees in St. Clair County
| Period | St. Clair County | St. Louis area | Illinois | U.S. |
|---|---|---|---|---|
| 2006–10 | 25.8% | 30.3% | 31.2% | 28.4% |
| 2010–14 | 27.3% | 32.1% | 32.4% | 29.6% |
| 2015–19 | 29.5% | 34.9% | 34.7% | 32.1% |
| 2020–24 | 33.0% | 38.5% | 37.7% | 35.6% |
| Change | +7.2 pts | +8.3 pts | +6.5 pts | +7.2 pts |
College degrees are about as common in St. Clair County as nationally: 33.0% of adults 25 and older have a bachelor's or higher, against 35.6%. The share is lower than in the St. Louis area as a whole (38.5%). The share with a degree is up 7.2 points from 2006–10, in line with the national trend.
Bachelor's degrees: adults 25 and older with a bachelor's degree or higher. Source: BestNeighborhood calculations from U.S. Census Bureau ACS 5-year block-group estimates (table B15003).
High school graduates in St. Clair County
| Period | St. Clair County | St. Louis area | Illinois | U.S. |
|---|---|---|---|---|
| 2006–10 | 88.6% | 88.8% | 86.3% | 84.9% |
| 2010–14 | 90.5% | 90.5% | 87.5% | 86.1% |
| 2015–19 | 91.5% | 92.1% | 89.1% | 87.7% |
| 2020–24 | 93.4% | 93.6% | 90.3% | 89.3% |
| Change | +4.9 pts | +4.8 pts | +4.0 pts | +4.3 pts |
High school completion in St. Clair County is above the national rate: 93.4% of adults have a diploma or equivalent, against 89.3%. That is in line with the rest of the St. Louis area. The share with a diploma has risen 4.9 points since 2006–10, as it has nationally.
High school graduates: adults 25 and older with a high school diploma, GED or more. Source: BestNeighborhood calculations from U.S. Census Bureau ACS 5-year block-group estimates (table B15003).
Jobs in St. Clair County
| Period | St. Clair County | St. Louis area | Illinois | U.S. |
|---|---|---|---|---|
| 2006–10 | 8.6% | 7.7% | 8.7% | 8.1% |
| 2010–14 | 9.2% | 8.8% | 10.2% | 9.4% |
| 2015–19 | 6.3% | 4.9% | 6.1% | 5.6% |
| 2020–24 | 5.6% | 4.3% | 6.0% | 5.4% |
| Change | −3.0 pts | −3.4 pts | −2.7 pts | −2.7 pts |
Unemployment in St. Clair County is close to the national rate: 5.6% of the labor force, against 5.4%. The rate is higher than in the wider St. Louis area (4.3%). Unemployment is down 3.0 points from 2006–10, as it has nationally.
Unemployment: people looking for work as a share of everyone working or looking. Source: BestNeighborhood calculations from U.S. Census Bureau ACS 5-year block-group estimates (table B23025).
St. Clair County compared with nearby counties
| County | Household size | Median age | Single parents | Renters | Vacant homes | Median year built | Median rent | Bachelor's degree | High school diploma | Unemployment |
|---|---|---|---|---|---|---|---|---|---|---|
| St. Clair County | 2.57 | 40.2 | 13.5% | 31.6% | 11.5% | 1978 | $1,199 | 33.0% | 93.4% | 5.6% |
| St. Louis City | 2.02 | 38.2 | 13.3% | 54.7% | 16.3% | 1946 | $1,044 | 41.0% | 90.7% | 5.9% |
| St. Louis County | 2.44 | 41.3 | 11.4% | 30.8% | 8.0% | 1969 | $1,388 | 47.6% | 94.5% | 4.4% |
| Clinton County | 2.42 | 42.1 | 7.3% | 19.7% | 8.3% | 1978 | $931 | 26.7% | 92.9% | 3.6% |
| Marion County | 2.39 | 40.7 | 13.2% | 25.3% | 11.1% | 1973 | $841 | 16.8% | 90.3% | 6.0% |
| Franklin County | 2.46 | 41.8 | 10.7% | 23.5% | 8.0% | 1983 | $947 | 23.7% | 90.5% | 4.3% |
| Gasconade County | 2.42 | 46.0 | 10.1% | 19.1% | 18.7% | 1976 | $797 | 17.3% | 90.4% | 3.1% |
| Wayne County | 2.37 | 42.5 | 8.6% | 21.6% | 10.3% | 1976 | $704 | 16.1% | 89.1% | 3.5% |
| Osage County | 2.54 | 40.9 | 6.5% | 20.6% | 20.9% | 1982 | $700 | 24.8% | 90.9% | 1.9% |
| Edwards County | 2.30 | 45.3 | 9.6% | 20.7% | 11.6% | 1969 | $704 | 14.2% | 92.0% | 4.8% |
| Wabash County | 2.32 | 42.3 | 13.2% | 23.7% | 13.5% | 1965 | $793 | 17.6% | 92.6% | 3.8% |
All figures 2020–24.
Counties with similar populations: Horry County, SC · Richmond County, GA · Richmond City, VA · Racine County, WI · Onslow County, NC · Okaloosa County, FL · Niagara County, NY · New Hanover County, NC · Muscogee County, GA · Leon County, FL
About these numbers
Every figure on this page is a BestNeighborhood calculation from the Census Bureau's American Community Survey (ACS), built up from the Census block groups that make up St. Clair County. Each ACS 5-year release pools five years of responses; this page shows the last 15 releases, 2006–10 through 2020–24. Neighboring releases share four of their five years, so they move gradually and small changes between them are within the survey's margin of error; in small places the lines can jump from one release to the next for the same reason. The maps show the same measures for each neighborhood, ranked against the whole country.
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