| | Roslyn Estates, NY | Dix Hills, NY | United States |
| Population | 1,382 | 24,739 | 329,725,481 |
| Female Population | 52.3% | 48.6% | 50.5% |
| Male Population | 47.7% | 51.4% | 49.5% |
| Median Age | 43.9 | 46.8 | 38.4 |
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| Population - 2010 | 1,212 | 26,548 | 309,327,143 |
| Population - 2000 | 1,210 | 26,024 | 285,036,114 |
| Population - 1990 | 1,184 | 25,849 | 251,960,433 |
| Pop. 2000 to Now | -0.2% | 5.0% | 15.6% |
| Pop. 1990 to Now | 2.0% | 5.7% | 30.8% |
| space4 | | | |
| Population Density | 3,162.5 | 1,552.2 | 93.4 |
| Land Area | 0.4 | 15.9 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Roslyn Estates, NY | Dix Hills, NY | United States |
| Age 0 to 4 | 4.5% | 4.6% | 5.9% |
| Age 5 to 9 | 8.2% | 6.8% | 6.1% |
| Age 10 to 14 | 7.2% | 6.7% | 6.6% |
| Age 15 to 17 | 4.3% | 4.6% | 3.9% |
| Age 18 to 20 | 3.0% | 3.0% | 4.0% |
| Age 21 to 24 | 4.8% | 4.0% | 5.2% |
| Age 25 to 34 | 5.6% | 8.0% | 13.8% |
| Age 35 to 44 | 12.7% | 10.3% | 12.9% |
| Age 45 to 54 | 14.8% | 16.1% | 12.6% |
| Age 55 to 59 | 10.6% | 8.2% | 6.7% |
| Age 60 to 64 | 5.9% | 9.4% | 6.3% |
| Age 65 to 74 | 8.3% | 10.4% | 9.6% |
| Age 75 to 84 | 6.9% | 6.4% | 4.5% |
| Age 85 and over | 3.1% | 1.4% | 1.9% |
| space1 | | | |
| Race | | | |
| | Roslyn Estates, NY | Dix Hills, NY | United States |
| White | 89.4% | 71.4% | 59.4% |
| Black | 0.3% | 3.7% | 12.2% |
| Asian | 6.0% | 15.1% | 5.6% |
| Native American | 0.0% | 0.8% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.3% | 0.4% |
| Two or More Races | 0.9% | 2.6% | 3.2% |
| Hispanic | 3.5% | 6.1% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Roslyn Estates, NY | Dix Hills, NY | United States |
| Married Population | 72.7% | 64.1% | 49.8% |
| Currently Married | 72.7% | 63.1% | 48.0% |
| Married but Separated | 0.0% | 1.1% | 1.8% |
| Single Population | 27.3% | 35.9% | 50.2% |
| Never Married | 22.7% | 24.5% | 33.8% |
| Divorced | 2.4% | 6.3% | 10.8% |
| Widowed | 2.2% | 5.1% | 5.6% |
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| Household Size | 3.14 | 3.15 | 2.60 |
| Households | 440 | 7,765 | 124,010,992 |
| Family Households | 406 | 6,698 | 80,755,759 |
| Married couple, w/children | 34.5% | 38.7% | 30.5% |
| Married couple, no children | 60.6% | 51.2% | 42.9% |
| Non Family Households | 34 | 1,067 | 43,255,233 |
| Single householder, w/children | 4.9% | 4.5% | 15.8% |
| Single householder, no children | 0.0% | 5.6% | 10.8% |