| | Forney, TX | Lancaster, TX | United States |
| Population | 22,770 | 41,057 | 329,725,481 |
| Female Population | 47.4% | 55.5% | 50.5% |
| Male Population | 52.6% | 44.5% | 49.5% |
| Median Age | 32.3 | 32.5 | 38.4 |
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| Population - 2010 | 13,946 | 36,774 | 309,327,143 |
| Population - 2000 | 5,588 | 25,894 | 285,036,114 |
| Population - 1990 | 4,070 | 22,117 | 251,960,433 |
| Pop. 2000 to Now | 423.4% | 51.6% | 15.6% |
| Pop. 1990 to Now | 618.6% | 77.5% | 30.8% |
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| Population Density | 1,538.8 | 1,235.6 | 93.4 |
| Land Area | 14.8 | 33.2 | 3,531,905.4 |
| Water Area | 0.0 | 0.1 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Forney, TX | Lancaster, TX | United States |
| Age 0 to 4 | 9.2% | 9.5% | 5.9% |
| Age 5 to 9 | 7.7% | 7.9% | 6.1% |
| Age 10 to 14 | 6.2% | 8.1% | 6.6% |
| Age 15 to 17 | 4.9% | 5.6% | 3.9% |
| Age 18 to 20 | 4.7% | 3.8% | 4.0% |
| Age 21 to 24 | 5.7% | 3.8% | 5.2% |
| Age 25 to 34 | 17.0% | 14.0% | 13.8% |
| Age 35 to 44 | 15.3% | 13.3% | 12.9% |
| Age 45 to 54 | 12.2% | 11.3% | 12.6% |
| Age 55 to 59 | 5.0% | 7.4% | 6.7% |
| Age 60 to 64 | 4.1% | 5.7% | 6.3% |
| Age 65 to 74 | 5.4% | 6.5% | 9.6% |
| Age 75 to 84 | 2.0% | 2.2% | 4.5% |
| Age 85 and over | 0.7% | 1.1% | 1.9% |
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| Race | | | |
| | Forney, TX | Lancaster, TX | United States |
| White | 62.2% | 7.8% | 59.4% |
| Black | 15.6% | 67.8% | 12.2% |
| Asian | 2.0% | 1.0% | 5.6% |
| Native American | 0.0% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.1% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 1.8% | 2.1% | 3.2% |
| Hispanic | 18.4% | 21.2% | 18.4% |
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| Marriage & Family | | | |
| | Forney, TX | Lancaster, TX | United States |
| Married Population | 56.1% | 45.4% | 49.8% |
| Currently Married | 56.0% | 42.4% | 48.0% |
| Married but Separated | 0.1% | 3.0% | 1.8% |
| Single Population | 43.9% | 54.6% | 50.2% |
| Never Married | 28.6% | 37.2% | 33.8% |
| Divorced | 12.2% | 12.9% | 10.8% |
| Widowed | 3.1% | 4.5% | 5.6% |
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| Household Size | 2.90 | 2.90 | 2.60 |
| Households | 7,860 | 13,998 | 124,010,992 |
| Family Households | 5,931 | 9,979 | 80,755,759 |
| Married couple, w/children | 46.3% | 32.0% | 30.5% |
| Married couple, no children | 31.3% | 24.3% | 42.9% |
| Non Family Households | 1,929 | 4,019 | 43,255,233 |
| Single householder, w/children | 17.7% | 32.8% | 15.8% |
| Single householder, no children | 4.7% | 10.8% | 10.8% |