| | Hayfield, VA | Mount Vernon, VA | United States |
| Population | 4,348 | 13,707 | 329,725,481 |
| Female Population | 48.3% | 52.4% | 50.5% |
| Male Population | 51.8% | 47.6% | 49.5% |
| Median Age | 38.4 | 42.8 | 38.4 |
| space3 | | | |
| Population - 2010 | 3,848 | 11,753 | 309,327,143 |
| Population - 2000 | 4,232 | 28,582 | 285,036,114 |
| Population - 1990 | 4,114 | 27,485 | 251,960,433 |
| Pop. 2000 to Now | 1.7% | -55.4% | 15.6% |
| Pop. 1990 to Now | 4.6% | -53.6% | 30.8% |
| space4 | | | |
| Population Density | 3,362.7 | 2,623.4 | 93.4 |
| Land Area | 1.3 | 5.2 | 3,531,905.4 |
| Water Area | 0.1 | 0.8 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Hayfield, VA | Mount Vernon, VA | United States |
| Age 0 to 4 | 8.3% | 7.6% | 5.9% |
| Age 5 to 9 | 7.8% | 6.4% | 6.1% |
| Age 10 to 14 | 5.0% | 6.6% | 6.6% |
| Age 15 to 17 | 3.5% | 4.4% | 3.9% |
| Age 18 to 20 | 5.8% | 1.7% | 4.0% |
| Age 21 to 24 | 3.2% | 3.7% | 5.2% |
| Age 25 to 34 | 11.5% | 9.7% | 13.8% |
| Age 35 to 44 | 11.8% | 12.5% | 12.9% |
| Age 45 to 54 | 13.7% | 17.3% | 12.6% |
| Age 55 to 59 | 6.0% | 6.9% | 6.7% |
| Age 60 to 64 | 4.9% | 6.4% | 6.3% |
| Age 65 to 74 | 11.8% | 9.4% | 9.6% |
| Age 75 to 84 | 5.7% | 4.6% | 4.5% |
| Age 85 and over | 1.2% | 2.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Hayfield, VA | Mount Vernon, VA | United States |
| White | 77.3% | 54.9% | 59.4% |
| Black | 6.9% | 14.7% | 12.2% |
| Asian | 4.2% | 6.4% | 5.6% |
| Native American | 0.0% | 0.2% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.5% | 0.4% |
| Two or More Races | 6.7% | 5.5% | 3.2% |
| Hispanic | 4.8% | 17.8% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Hayfield, VA | Mount Vernon, VA | United States |
| Married Population | 61.4% | 61.9% | 49.8% |
| Currently Married | 59.9% | 60.0% | 48.0% |
| Married but Separated | 1.5% | 1.9% | 1.8% |
| Single Population | 38.6% | 38.1% | 50.2% |
| Never Married | 28.3% | 23.5% | 33.8% |
| Divorced | 6.9% | 8.8% | 10.8% |
| Widowed | 3.4% | 5.8% | 5.6% |
| space5 | | | |
| Household Size | 3.04 | 2.83 | 2.60 |
| Households | 1,416 | 4,847 | 124,010,992 |
| Family Households | 1,178 | 3,597 | 80,755,759 |
| Married couple, w/children | 36.4% | 36.3% | 30.5% |
| Married couple, no children | 45.8% | 45.5% | 42.9% |
| Non Family Households | 238 | 1,250 | 43,255,233 |
| Single householder, w/children | 9.3% | 11.1% | 15.8% |
| Single householder, no children | 8.4% | 7.1% | 10.8% |