| | Elmsford, NY | Valhalla, NY | United States |
| Population | 5,176 | 3,135 | 329,725,481 |
| Female Population | 52.4% | 47.4% | 50.5% |
| Male Population | 47.6% | 52.6% | 49.5% |
| Median Age | 34.3 | 40.7 | 38.4 |
| space3 | | | |
| Population - 2010 | 4,706 | 3,083 | 309,327,143 |
| Population - 2000 | 4,676 | 5,379 | 285,036,114 |
| Population - 1990 | 3,938 | 2,791 | 251,960,433 |
| Pop. 2000 to Now | 11.1% | -38.8% | 15.6% |
| Pop. 1990 to Now | 31.9% | 18.0% | 30.8% |
| space4 | | | |
| Population Density | 5,010.7 | 3,809.2 | 93.4 |
| Land Area | 1.0 | 0.8 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Elmsford, NY | Valhalla, NY | United States |
| Age 0 to 4 | 7.1% | 8.1% | 5.9% |
| Age 5 to 9 | 5.1% | 4.3% | 6.1% |
| Age 10 to 14 | 7.6% | 6.3% | 6.6% |
| Age 15 to 17 | 2.9% | 2.6% | 3.9% |
| Age 18 to 20 | 5.5% | 3.2% | 4.0% |
| Age 21 to 24 | 6.8% | 3.6% | 5.2% |
| Age 25 to 34 | 17.1% | 16.0% | 13.8% |
| Age 35 to 44 | 14.5% | 10.1% | 12.9% |
| Age 45 to 54 | 15.0% | 9.4% | 12.6% |
| Age 55 to 59 | 5.3% | 8.3% | 6.7% |
| Age 60 to 64 | 4.2% | 8.4% | 6.3% |
| Age 65 to 74 | 5.0% | 9.4% | 9.6% |
| Age 75 to 84 | 2.7% | 4.5% | 4.5% |
| Age 85 and over | 1.2% | 5.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Elmsford, NY | Valhalla, NY | United States |
| White | 22.1% | 74.3% | 59.4% |
| Black | 19.9% | 7.4% | 12.2% |
| Asian | 10.5% | 2.2% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.4% | 0.0% | 0.4% |
| Two or More Races | 3.2% | 1.0% | 3.2% |
| Hispanic | 43.9% | 15.2% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Elmsford, NY | Valhalla, NY | United States |
| Married Population | 45.7% | 58.3% | 49.8% |
| Currently Married | 44.6% | 55.5% | 48.0% |
| Married but Separated | 1.1% | 2.9% | 1.8% |
| Single Population | 54.3% | 41.7% | 50.2% |
| Never Married | 43.9% | 29.2% | 33.8% |
| Divorced | 6.9% | 5.6% | 10.8% |
| Widowed | 3.5% | 6.9% | 5.6% |
| space5 | | | |
| Household Size | 3.26 | 2.92 | 2.60 |
| Households | 1,583 | 1,075 | 124,010,992 |
| Family Households | 1,232 | 773 | 80,755,759 |
| Married couple, w/children | 28.2% | 28.2% | 30.5% |
| Married couple, no children | 36.3% | 47.1% | 42.9% |
| Non Family Households | 351 | 302 | 43,255,233 |
| Single householder, w/children | 23.7% | 16.0% | 15.8% |
| Single householder, no children | 11.8% | 8.7% | 10.8% |