| | Flossmoor, IL | Country Club Hills, IL | United States |
| Population | 9,868 | 16,746 | 329,725,481 |
| Female Population | 52.9% | 55.3% | 50.5% |
| Male Population | 47.2% | 44.7% | 49.5% |
| Median Age | 43 | 40.8 | 38.4 |
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| Population - 2010 | 9,421 | 16,747 | 309,327,143 |
| Population - 2000 | 9,301 | 16,169 | 285,036,114 |
| Population - 1990 | 8,651 | 15,431 | 251,960,433 |
| Pop. 2000 to Now | -3.0% | 0.5% | 15.6% |
| Pop. 1990 to Now | 4.2% | 5.3% | 30.8% |
| space4 | | | |
| Population Density | 2,695.4 | 3,382.4 | 93.4 |
| Land Area | 3.7 | 5.0 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Flossmoor, IL | Country Club Hills, IL | United States |
| Age 0 to 4 | 7.9% | 4.5% | 5.9% |
| Age 5 to 9 | 6.7% | 5.2% | 6.1% |
| Age 10 to 14 | 6.2% | 7.7% | 6.6% |
| Age 15 to 17 | 5.2% | 5.4% | 3.9% |
| Age 18 to 20 | 4.8% | 4.4% | 4.0% |
| Age 21 to 24 | 2.0% | 3.7% | 5.2% |
| Age 25 to 34 | 5.8% | 11.8% | 13.8% |
| Age 35 to 44 | 12.7% | 13.2% | 12.9% |
| Age 45 to 54 | 16.0% | 10.7% | 12.6% |
| Age 55 to 59 | 7.1% | 7.1% | 6.7% |
| Age 60 to 64 | 8.2% | 8.9% | 6.3% |
| Age 65 to 74 | 12.2% | 10.9% | 9.6% |
| Age 75 to 84 | 3.2% | 5.4% | 4.5% |
| Age 85 and over | 2.1% | 1.1% | 1.9% |
| space1 | | | |
| Race | | | |
| | Flossmoor, IL | Country Club Hills, IL | United States |
| White | 28.6% | 5.7% | 59.4% |
| Black | 64.1% | 87.7% | 12.2% |
| Asian | 1.9% | 2.1% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.1% | 0.0% | 0.4% |
| Two or More Races | 3.6% | 1.0% | 3.2% |
| Hispanic | 1.6% | 3.5% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Flossmoor, IL | Country Club Hills, IL | United States |
| Married Population | 59.7% | 33.2% | 49.8% |
| Currently Married | 57.8% | 30.5% | 48.0% |
| Married but Separated | 1.8% | 2.7% | 1.8% |
| Single Population | 40.3% | 66.8% | 50.2% |
| Never Married | 26.9% | 47.1% | 33.8% |
| Divorced | 8.2% | 12.1% | 10.8% |
| Widowed | 5.2% | 7.6% | 5.6% |
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| Household Size | 2.79 | 2.90 | 2.60 |
| Households | 3,519 | 5,717 | 124,010,992 |
| Family Households | 2,621 | 3,716 | 80,755,759 |
| Married couple, w/children | 37.6% | 19.9% | 30.5% |
| Married couple, no children | 45.9% | 30.9% | 42.9% |
| Non Family Households | 898 | 2,001 | 43,255,233 |
| Single householder, w/children | 13.7% | 23.3% | 15.8% |
| Single householder, no children | 2.7% | 25.8% | 10.8% |