| | St. Ann, MO | Ferguson, MO | United States |
| Population | 13,007 | 18,826 | 329,725,481 |
| Female Population | 53.1% | 55.3% | 50.5% |
| Male Population | 46.9% | 44.7% | 49.5% |
| Median Age | 35.2 | 34.2 | 38.4 |
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| Population - 2010 | 13,020 | 21,181 | 309,327,143 |
| Population - 2000 | 13,607 | 22,406 | 285,036,114 |
| Population - 1990 | 14,489 | 22,286 | 251,960,433 |
| Pop. 2000 to Now | -7.5% | -8.7% | 15.6% |
| Pop. 1990 to Now | -13.2% | -8.2% | 30.8% |
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| Population Density | 4,085.1 | 3,041.4 | 93.4 |
| Land Area | 3.2 | 6.2 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | St. Ann, MO | Ferguson, MO | United States |
| Age 0 to 4 | 7.9% | 8.6% | 5.9% |
| Age 5 to 9 | 7.9% | 6.4% | 6.1% |
| Age 10 to 14 | 4.8% | 7.4% | 6.6% |
| Age 15 to 17 | 2.8% | 4.9% | 3.9% |
| Age 18 to 20 | 2.6% | 5.1% | 4.0% |
| Age 21 to 24 | 5.5% | 3.3% | 5.2% |
| Age 25 to 34 | 18.2% | 16.1% | 13.8% |
| Age 35 to 44 | 9.5% | 12.8% | 12.9% |
| Age 45 to 54 | 10.8% | 10.5% | 12.6% |
| Age 55 to 59 | 7.3% | 6.2% | 6.7% |
| Age 60 to 64 | 6.8% | 5.1% | 6.3% |
| Age 65 to 74 | 8.3% | 9.6% | 9.6% |
| Age 75 to 84 | 5.3% | 2.5% | 4.5% |
| Age 85 and over | 2.3% | 1.5% | 1.9% |
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| Race | | | |
| | St. Ann, MO | Ferguson, MO | United States |
| White | 55.4% | 21.5% | 59.4% |
| Black | 33.4% | 70.6% | 12.2% |
| Asian | 2.3% | 0.4% | 5.6% |
| Native American | 0.0% | 0.4% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.1% | 1.2% | 0.4% |
| Two or More Races | 3.4% | 4.5% | 3.2% |
| Hispanic | 5.5% | 1.4% | 18.4% |
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| Marriage & Family | | | |
| | St. Ann, MO | Ferguson, MO | United States |
| Married Population | 40.3% | 36.5% | 49.8% |
| Currently Married | 38.2% | 31.5% | 48.0% |
| Married but Separated | 2.2% | 5.0% | 1.8% |
| Single Population | 59.7% | 63.5% | 50.2% |
| Never Married | 39.3% | 45.1% | 33.8% |
| Divorced | 13.2% | 13.6% | 10.8% |
| Widowed | 7.1% | 4.8% | 5.6% |
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| Household Size | 2.22 | 2.33 | 2.60 |
| Households | 5,846 | 8,004 | 124,010,992 |
| Family Households | 3,412 | 4,802 | 80,755,759 |
| Married couple, w/children | 19.9% | 12.6% | 30.5% |
| Married couple, no children | 31.4% | 29.9% | 42.9% |
| Non Family Households | 2,434 | 3,202 | 43,255,233 |
| Single householder, w/children | 31.5% | 41.3% | 15.8% |
| Single householder, no children | 17.2% | 16.2% | 10.8% |