| | Harriman, NY | Landover, MD | United States |
| Population | 3,168 | 24,508 | 329,725,481 |
| Female Population | 56.1% | 52.5% | 50.5% |
| Male Population | 43.9% | 47.5% | 49.5% |
| Median Age | 37.7 | 35.3 | 38.4 |
| space3 | | | |
| Population - 2010 | 2,423 | 23,540 | 309,327,143 |
| Population - 2000 | 2,252 | 22,368 | 285,036,114 |
| Population - 1990 | 2,288 | 5,052 | 251,960,433 |
| Pop. 2000 to Now | 7.5% | 2.5% | 15.6% |
| Pop. 1990 to Now | 5.8% | 353.8% | 30.8% |
| space4 | | | |
| Population Density | 3,155.4 | 6,128.5 | 93.4 |
| Land Area | 1.0 | 4.0 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Harriman, NY | Landover, MD | United States |
| Age 0 to 4 | 8.0% | 7.9% | 5.9% |
| Age 5 to 9 | 9.0% | 7.3% | 6.1% |
| Age 10 to 14 | 7.5% | 7.5% | 6.6% |
| Age 15 to 17 | 5.5% | 4.7% | 3.9% |
| Age 18 to 20 | 1.2% | 3.0% | 4.0% |
| Age 21 to 24 | 2.6% | 4.7% | 5.2% |
| Age 25 to 34 | 11.6% | 14.5% | 13.8% |
| Age 35 to 44 | 18.5% | 15.3% | 12.9% |
| Age 45 to 54 | 11.5% | 13.4% | 12.6% |
| Age 55 to 59 | 8.4% | 5.9% | 6.7% |
| Age 60 to 64 | 5.4% | 5.0% | 6.3% |
| Age 65 to 74 | 6.5% | 6.3% | 9.6% |
| Age 75 to 84 | 1.7% | 3.3% | 4.5% |
| Age 85 and over | 2.8% | 1.2% | 1.9% |
| space1 | | | |
| Race | | | |
| | Harriman, NY | Landover, MD | United States |
| White | 38.6% | 2.8% | 59.4% |
| Black | 22.1% | 69.3% | 12.2% |
| Asian | 11.3% | 4.0% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 1.8% | 0.2% | 0.4% |
| Two or More Races | 0.6% | 2.7% | 3.2% |
| Hispanic | 25.6% | 21.1% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Harriman, NY | Landover, MD | United States |
| Married Population | 49.6% | 41.5% | 49.8% |
| Currently Married | 46.2% | 37.4% | 48.0% |
| Married but Separated | 3.3% | 4.1% | 1.8% |
| Single Population | 50.4% | 58.5% | 50.2% |
| Never Married | 31.0% | 44.1% | 33.8% |
| Divorced | 13.3% | 9.3% | 10.8% |
| Widowed | 6.1% | 5.1% | 5.6% |
| space5 | | | |
| Household Size | 2.78 | 2.81 | 2.60 |
| Households | 1,140 | 8,684 | 124,010,992 |
| Family Households | 679 | 5,438 | 80,755,759 |
| Married couple, w/children | 40.1% | 29.2% | 30.5% |
| Married couple, no children | 25.2% | 25.0% | 42.9% |
| Non Family Households | 461 | 3,246 | 43,255,233 |
| Single householder, w/children | 19.6% | 24.5% | 15.8% |
| Single householder, no children | 15.2% | 21.3% | 10.8% |