| | Greenwich, NY | Harpers Ferry, WV | United States |
| Population | 4,878 | 292 | 329,725,481 |
| Female Population | 49.6% | 51.0% | 50.5% |
| Male Population | 50.4% | 49.0% | 49.5% |
| Median Age | 41.6 | 57.7 | 38.4 |
| space3 | | | |
| Population - 2010 | 4,959 | 288 | 309,327,143 |
| Population - 2000 | 4,896 | 307 | 285,036,114 |
| Population - 1990 | 4,557 | 308 | 251,960,433 |
| Pop. 2000 to Now | -3.1% | -7.2% | 15.6% |
| Pop. 1990 to Now | 4.1% | -7.5% | 30.8% |
| space4 | | | |
| Population Density | 111.7 | 545.8 | 93.4 |
| Land Area | 43.7 | 0.5 | 3,531,905.4 |
| Water Area | 0.6 | 0.1 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Greenwich, NY | Harpers Ferry, WV | United States |
| Age 0 to 4 | 6.0% | 3.1% | 5.9% |
| Age 5 to 9 | 6.9% | 4.5% | 6.1% |
| Age 10 to 14 | 6.2% | 2.4% | 6.6% |
| Age 15 to 17 | 1.9% | 3.8% | 3.9% |
| Age 18 to 20 | 2.2% | 0.3% | 4.0% |
| Age 21 to 24 | 6.4% | 1.0% | 5.2% |
| Age 25 to 34 | 11.0% | 6.2% | 13.8% |
| Age 35 to 44 | 13.0% | 7.5% | 12.9% |
| Age 45 to 54 | 16.1% | 10.3% | 12.6% |
| Age 55 to 59 | 4.5% | 17.5% | 6.7% |
| Age 60 to 64 | 6.2% | 6.2% | 6.3% |
| Age 65 to 74 | 14.0% | 22.6% | 9.6% |
| Age 75 to 84 | 3.8% | 13.7% | 4.5% |
| Age 85 and over | 1.8% | 1.0% | 1.9% |
| space1 | | | |
| Race | | | |
| | Greenwich, NY | Harpers Ferry, WV | United States |
| White | 95.5% | 97.6% | 59.4% |
| Black | 0.8% | 0.0% | 12.2% |
| Asian | 1.1% | 0.7% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 1.0% | 1.0% | 3.2% |
| Hispanic | 1.6% | 0.7% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Greenwich, NY | Harpers Ferry, WV | United States |
| Married Population | 56.0% | 77.9% | 49.8% |
| Currently Married | 53.2% | 73.4% | 48.0% |
| Married but Separated | 2.7% | 4.6% | 1.8% |
| Single Population | 44.0% | 22.1% | 50.2% |
| Never Married | 28.8% | 12.5% | 33.8% |
| Divorced | 9.4% | 7.6% | 10.8% |
| Widowed | 5.8% | 1.9% | 5.6% |
| space5 | | | |
| Household Size | 2.58 | 2.39 | 2.60 |
| Households | 1,888 | 122 | 124,010,992 |
| Family Households | 1,267 | 90 | 80,755,759 |
| Married couple, w/children | 28.3% | 14.4% | 30.5% |
| Married couple, no children | 51.5% | 80.0% | 42.9% |
| Non Family Households | 621 | 32 | 43,255,233 |
| Single householder, w/children | 12.6% | 4.4% | 15.8% |
| Single householder, no children | 7.7% | 1.1% | 10.8% |