| | Elsmere, DE | Valley Stream, NY | United States |
| Population | 6,167 | 40,304 | 329,725,481 |
| Female Population | 49.7% | 53.2% | 50.5% |
| Male Population | 50.3% | 46.8% | 49.5% |
| Median Age | 34.1 | 42 | 38.4 |
| space3 | | | |
| Population - 2010 | 5,970 | 37,426 | 309,327,143 |
| Population - 2000 | 5,800 | 36,368 | 285,036,114 |
| Population - 1990 | 5,935 | 33,946 | 251,960,433 |
| Pop. 2000 to Now | -0.7% | 2.3% | 15.6% |
| Pop. 1990 to Now | -2.9% | 9.6% | 30.8% |
| space4 | | | |
| Population Density | 6,130.2 | 11,584.9 | 93.4 |
| Land Area | 1.0 | 3.5 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Elsmere, DE | Valley Stream, NY | United States |
| Age 0 to 4 | 4.4% | 4.7% | 5.9% |
| Age 5 to 9 | 8.7% | 4.6% | 6.1% |
| Age 10 to 14 | 5.9% | 6.2% | 6.6% |
| Age 15 to 17 | 7.8% | 4.3% | 3.9% |
| Age 18 to 20 | 4.4% | 4.1% | 4.0% |
| Age 21 to 24 | 3.6% | 4.8% | 5.2% |
| Age 25 to 34 | 17.5% | 12.4% | 13.8% |
| Age 35 to 44 | 14.2% | 13.0% | 12.9% |
| Age 45 to 54 | 10.7% | 15.7% | 12.6% |
| Age 55 to 59 | 5.8% | 6.3% | 6.7% |
| Age 60 to 64 | 6.7% | 8.6% | 6.3% |
| Age 65 to 74 | 6.8% | 10.1% | 9.6% |
| Age 75 to 84 | 2.8% | 2.9% | 4.5% |
| Age 85 and over | 0.8% | 2.3% | 1.9% |
| space1 | | | |
| Race | | | |
| | Elsmere, DE | Valley Stream, NY | United States |
| White | 56.1% | 28.5% | 59.4% |
| Black | 13.2% | 26.5% | 12.2% |
| Asian | 1.2% | 14.7% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.1% | 3.0% | 0.4% |
| Two or More Races | 0.8% | 5.0% | 3.2% |
| Hispanic | 28.5% | 22.3% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Elsmere, DE | Valley Stream, NY | United States |
| Married Population | 31.1% | 53.7% | 49.8% |
| Currently Married | 30.1% | 52.7% | 48.0% |
| Married but Separated | 1.0% | 1.0% | 1.8% |
| Single Population | 68.9% | 46.3% | 50.2% |
| Never Married | 49.9% | 33.1% | 33.8% |
| Divorced | 13.9% | 7.5% | 10.8% |
| Widowed | 5.1% | 5.7% | 5.6% |
| space5 | | | |
| Household Size | 2.67 | 3.21 | 2.60 |
| Households | 2,304 | 12,520 | 124,010,992 |
| Family Households | 1,311 | 10,137 | 80,755,759 |
| Married couple, w/children | 23.9% | 35.3% | 30.5% |
| Married couple, no children | 25.8% | 38.7% | 42.9% |
| Non Family Households | 993 | 2,383 | 43,255,233 |
| Single householder, w/children | 29.2% | 11.8% | 15.8% |
| Single householder, no children | 21.1% | 14.3% | 10.8% |