| | Millington, TN | Springfield, IL | United States |
| Population | 10,583 | 114,672 | 329,725,481 |
| Female Population | 51.0% | 52.1% | 50.5% |
| Male Population | 49.0% | 47.9% | 49.5% |
| Median Age | 38.2 | 39.7 | 38.4 |
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| Population - 2010 | 10,779 | 117,139 | 309,327,143 |
| Population - 2000 | 10,433 | 111,454 | 285,036,114 |
| Population - 1990 | 17,866 | 105,227 | 251,960,433 |
| Pop. 2000 to Now | 1.9% | 2.0% | 15.6% |
| Pop. 1990 to Now | -40.5% | 8.0% | 30.8% |
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| Population Density | 472.4 | 1,880.5 | 93.4 |
| Land Area | 22.4 | 61.0 | 3,531,905.4 |
| Water Area | 0.0 | 6.3 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Millington, TN | Springfield, IL | United States |
| Age 0 to 4 | 4.8% | 6.1% | 5.9% |
| Age 5 to 9 | 6.6% | 6.3% | 6.1% |
| Age 10 to 14 | 9.6% | 6.0% | 6.6% |
| Age 15 to 17 | 5.1% | 3.8% | 3.9% |
| Age 18 to 20 | 3.2% | 3.9% | 4.0% |
| Age 21 to 24 | 4.0% | 4.9% | 5.2% |
| Age 25 to 34 | 13.5% | 13.3% | 13.8% |
| Age 35 to 44 | 9.7% | 11.9% | 12.9% |
| Age 45 to 54 | 13.2% | 12.1% | 12.6% |
| Age 55 to 59 | 9.3% | 7.5% | 6.7% |
| Age 60 to 64 | 6.4% | 6.5% | 6.3% |
| Age 65 to 74 | 9.3% | 10.5% | 9.6% |
| Age 75 to 84 | 2.5% | 5.2% | 4.5% |
| Age 85 and over | 2.7% | 2.1% | 1.9% |
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| Race | | | |
| | Millington, TN | Springfield, IL | United States |
| White | 54.1% | 70.4% | 59.4% |
| Black | 30.8% | 19.9% | 12.2% |
| Asian | 2.4% | 3.2% | 5.6% |
| Native American | 0.1% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.1% | 0.0% | 0.2% |
| Other | 0.0% | 0.2% | 0.4% |
| Two or More Races | 2.9% | 3.3% | 3.2% |
| Hispanic | 9.6% | 2.9% | 18.4% |
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| Marriage & Family | | | |
| | Millington, TN | Springfield, IL | United States |
| Married Population | 47.1% | 41.0% | 49.8% |
| Currently Married | 44.6% | 39.5% | 48.0% |
| Married but Separated | 2.5% | 1.6% | 1.8% |
| Single Population | 52.9% | 59.0% | 50.2% |
| Never Married | 31.3% | 37.6% | 33.8% |
| Divorced | 14.2% | 15.1% | 10.8% |
| Widowed | 7.4% | 6.2% | 5.6% |
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| Household Size | 2.52 | 2.18 | 2.60 |
| Households | 4,086 | 50,961 | 124,010,992 |
| Family Households | 2,783 | 27,450 | 80,755,759 |
| Married couple, w/children | 20.3% | 21.6% | 30.5% |
| Married couple, no children | 45.3% | 41.8% | 42.9% |
| Non Family Households | 1,303 | 23,511 | 43,255,233 |
| Single householder, w/children | 22.6% | 24.6% | 15.8% |
| Single householder, no children | 11.8% | 11.9% | 10.8% |