| | Caldwell, TX | Allen, TX | United States |
| Population | 4,013 | 102,778 | 329,725,481 |
| Female Population | 47.1% | 49.7% | 50.5% |
| Male Population | 53.0% | 50.3% | 49.5% |
| Median Age | 36.8 | 37.7 | 38.4 |
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| Population - 2010 | 4,115 | 84,923 | 309,327,143 |
| Population - 2000 | 3,449 | 43,554 | 285,036,114 |
| Population - 1990 | 3,181 | 18,309 | 251,960,433 |
| Pop. 2000 to Now | 30.3% | 151.1% | 15.6% |
| Pop. 1990 to Now | 41.3% | 497.4% | 30.8% |
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| Population Density | 1,029.5 | 3,894.7 | 93.4 |
| Land Area | 3.9 | 26.4 | 3,531,905.4 |
| Water Area | 0.0 | 0.1 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Caldwell, TX | Allen, TX | United States |
| Age 0 to 4 | 6.2% | 5.5% | 5.9% |
| Age 5 to 9 | 8.4% | 8.1% | 6.1% |
| Age 10 to 14 | 8.7% | 8.6% | 6.6% |
| Age 15 to 17 | 3.9% | 4.5% | 3.9% |
| Age 18 to 20 | 4.3% | 3.6% | 4.0% |
| Age 21 to 24 | 4.1% | 4.5% | 5.2% |
| Age 25 to 34 | 12.3% | 11.5% | 13.8% |
| Age 35 to 44 | 12.5% | 14.7% | 12.9% |
| Age 45 to 54 | 14.4% | 17.2% | 12.6% |
| Age 55 to 59 | 6.6% | 7.3% | 6.7% |
| Age 60 to 64 | 4.5% | 4.6% | 6.3% |
| Age 65 to 74 | 7.0% | 6.4% | 9.6% |
| Age 75 to 84 | 5.4% | 2.7% | 4.5% |
| Age 85 and over | 1.7% | 0.7% | 1.9% |
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| Race | | | |
| | Caldwell, TX | Allen, TX | United States |
| White | 52.6% | 54.6% | 59.4% |
| Black | 14.6% | 9.5% | 12.2% |
| Asian | 0.0% | 19.1% | 5.6% |
| Native American | 0.6% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.2% | 0.7% | 0.4% |
| Two or More Races | 3.3% | 4.8% | 3.2% |
| Hispanic | 28.8% | 11.2% | 18.4% |
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| Marriage & Family | | | |
| | Caldwell, TX | Allen, TX | United States |
| Married Population | 51.9% | 60.5% | 49.8% |
| Currently Married | 48.5% | 60.1% | 48.0% |
| Married but Separated | 3.4% | 0.4% | 1.8% |
| Single Population | 48.1% | 39.5% | 50.2% |
| Never Married | 29.5% | 26.8% | 33.8% |
| Divorced | 11.7% | 9.2% | 10.8% |
| Widowed | 7.0% | 3.5% | 5.6% |
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| Household Size | 2.45 | 3.04 | 2.60 |
| Households | 1,582 | 33,786 | 124,010,992 |
| Family Households | 874 | 26,642 | 80,755,759 |
| Married couple, w/children | 43.0% | 48.7% | 30.5% |
| Married couple, no children | 36.3% | 35.8% | 42.9% |
| Non Family Households | 708 | 7,144 | 43,255,233 |
| Single householder, w/children | 8.9% | 9.2% | 15.8% |
| Single householder, no children | 11.8% | 6.3% | 10.8% |