| | Potomac Mills, VA | Herndon, VA | United States |
| Population | 6,759 | 24,574 | 329,725,481 |
| Female Population | 47.9% | 48.4% | 50.5% |
| Male Population | 52.2% | 51.6% | 49.5% |
| Median Age | 35.9 | 35.7 | 38.4 |
| space3 | | | |
| Population - 2010 | 4,715 | 23,400 | 309,327,143 |
| Population - 2000 | 5,534 | 21,655 | 285,036,114 |
| Population - 1990 | 4,524 | 16,139 | 251,960,433 |
| Pop. 2000 to Now | 16.1% | 13.5% | 15.6% |
| Pop. 1990 to Now | 42.0% | 52.3% | 30.8% |
| space4 | | | |
| Population Density | 1,678.4 | 5,732.2 | 93.4 |
| Land Area | 4.0 | 4.3 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Potomac Mills, VA | Herndon, VA | United States |
| Age 0 to 4 | 4.8% | 6.9% | 5.9% |
| Age 5 to 9 | 8.6% | 7.2% | 6.1% |
| Age 10 to 14 | 12.2% | 5.7% | 6.6% |
| Age 15 to 17 | 6.6% | 4.0% | 3.9% |
| Age 18 to 20 | 4.1% | 3.1% | 4.0% |
| Age 21 to 24 | 2.3% | 6.0% | 5.2% |
| Age 25 to 34 | 11.0% | 15.9% | 13.8% |
| Age 35 to 44 | 19.1% | 16.5% | 12.9% |
| Age 45 to 54 | 11.2% | 12.8% | 12.6% |
| Age 55 to 59 | 5.6% | 6.5% | 6.7% |
| Age 60 to 64 | 4.4% | 5.4% | 6.3% |
| Age 65 to 74 | 7.3% | 6.8% | 9.6% |
| Age 75 to 84 | 2.1% | 2.9% | 4.5% |
| Age 85 and over | 0.7% | 0.4% | 1.9% |
| space1 | | | |
| Race | | | |
| | Potomac Mills, VA | Herndon, VA | United States |
| White | 48.0% | 35.4% | 59.4% |
| Black | 20.3% | 7.0% | 12.2% |
| Asian | 8.9% | 16.1% | 5.6% |
| Native American | 0.0% | 0.7% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.8% | 0.4% |
| Two or More Races | 1.8% | 3.3% | 3.2% |
| Hispanic | 21.0% | 36.7% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Potomac Mills, VA | Herndon, VA | United States |
| Married Population | 61.8% | 55.6% | 49.8% |
| Currently Married | 61.8% | 54.1% | 48.0% |
| Married but Separated | 0.0% | 1.5% | 1.8% |
| Single Population | 38.2% | 44.4% | 50.2% |
| Never Married | 27.5% | 34.8% | 33.8% |
| Divorced | 7.6% | 7.3% | 10.8% |
| Widowed | 3.1% | 2.3% | 5.6% |
| space5 | | | |
| Household Size | 3.48 | 3.10 | 2.60 |
| Households | 1,932 | 7,914 | 124,010,992 |
| Family Households | 1,586 | 5,747 | 80,755,759 |
| Married couple, w/children | 47.6% | 40.3% | 30.5% |
| Married couple, no children | 32.5% | 39.5% | 42.9% |
| Non Family Households | 346 | 2,167 | 43,255,233 |
| Single householder, w/children | 14.4% | 12.2% | 15.8% |
| Single householder, no children | 5.4% | 8.1% | 10.8% |