| | Holtsville, NY | Litchfield Park, AZ | United States |
| Population | 19,497 | 6,656 | 329,725,481 |
| Female Population | 50.6% | 49.1% | 50.5% |
| Male Population | 49.5% | 50.9% | 49.5% |
| Median Age | 39.3 | 45.1 | 38.4 |
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| Population - 2010 | 19,277 | 4,874 | 309,327,143 |
| Population - 2000 | 17,006 | 3,810 | 285,036,114 |
| Population - 1990 | 14,972 | 3,303 | 251,960,433 |
| Pop. 2000 to Now | 17.4% | 72.7% | 15.6% |
| Pop. 1990 to Now | 33.3% | 99.2% | 30.8% |
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| Population Density | 2,742.6 | 2,023.7 | 93.4 |
| Land Area | 7.1 | 3.3 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Holtsville, NY | Litchfield Park, AZ | United States |
| Age 0 to 4 | 5.7% | 3.9% | 5.9% |
| Age 5 to 9 | 6.2% | 7.4% | 6.1% |
| Age 10 to 14 | 6.4% | 6.0% | 6.6% |
| Age 15 to 17 | 3.9% | 4.5% | 3.9% |
| Age 18 to 20 | 3.8% | 3.0% | 4.0% |
| Age 21 to 24 | 5.5% | 2.7% | 5.2% |
| Age 25 to 34 | 11.8% | 7.8% | 13.8% |
| Age 35 to 44 | 13.6% | 14.6% | 12.9% |
| Age 45 to 54 | 16.5% | 14.5% | 12.6% |
| Age 55 to 59 | 7.5% | 6.9% | 6.7% |
| Age 60 to 64 | 6.2% | 6.6% | 6.3% |
| Age 65 to 74 | 8.2% | 13.2% | 9.6% |
| Age 75 to 84 | 3.5% | 5.9% | 4.5% |
| Age 85 and over | 1.2% | 3.0% | 1.9% |
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| Race | | | |
| | Holtsville, NY | Litchfield Park, AZ | United States |
| White | 77.9% | 65.2% | 59.4% |
| Black | 5.5% | 1.1% | 12.2% |
| Asian | 3.7% | 4.8% | 5.6% |
| Native American | 0.0% | 3.2% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.3% | 0.2% |
| Other | 0.1% | 0.8% | 0.4% |
| Two or More Races | 0.8% | 3.2% | 3.2% |
| Hispanic | 12.0% | 21.5% | 18.4% |
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| Marriage & Family | | | |
| | Holtsville, NY | Litchfield Park, AZ | United States |
| Married Population | 54.4% | 59.9% | 49.8% |
| Currently Married | 52.8% | 58.6% | 48.0% |
| Married but Separated | 1.6% | 1.3% | 1.8% |
| Single Population | 45.6% | 40.1% | 50.2% |
| Never Married | 30.8% | 22.1% | 33.8% |
| Divorced | 10.0% | 11.5% | 10.8% |
| Widowed | 4.8% | 6.5% | 5.6% |
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| Household Size | 3.00 | 2.49 | 2.60 |
| Households | 6,474 | 2,661 | 124,010,992 |
| Family Households | 5,001 | 1,812 | 80,755,759 |
| Married couple, w/children | 34.5% | 30.2% | 30.5% |
| Married couple, no children | 40.9% | 50.9% | 42.9% |
| Non Family Households | 1,473 | 849 | 43,255,233 |
| Single householder, w/children | 11.9% | 13.5% | 15.8% |
| Single householder, no children | 12.7% | 5.4% | 10.8% |