| | Stephens City, VA | Herndon, VA | United States |
| Population | 2,308 | 24,574 | 329,725,481 |
| Female Population | 53.2% | 48.4% | 50.5% |
| Male Population | 46.8% | 51.6% | 49.5% |
| Median Age | 32.1 | 35.7 | 38.4 |
| space3 | | | |
| Population - 2010 | 1,830 | 23,400 | 309,327,143 |
| Population - 2000 | 1,146 | 21,655 | 285,036,114 |
| Population - 1990 | 1,186 | 16,139 | 251,960,433 |
| Pop. 2000 to Now | 83.8% | 13.5% | 15.6% |
| Pop. 1990 to Now | 77.6% | 52.3% | 30.8% |
| space4 | | | |
| Population Density | 951.4 | 5,732.2 | 93.4 |
| Land Area | 2.4 | 4.3 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Stephens City, VA | Herndon, VA | United States |
| Age 0 to 4 | 5.4% | 6.9% | 5.9% |
| Age 5 to 9 | 9.6% | 7.2% | 6.1% |
| Age 10 to 14 | 7.5% | 5.7% | 6.6% |
| Age 15 to 17 | 3.6% | 4.0% | 3.9% |
| Age 18 to 20 | 2.3% | 3.1% | 4.0% |
| Age 21 to 24 | 6.7% | 6.0% | 5.2% |
| Age 25 to 34 | 17.7% | 15.9% | 13.8% |
| Age 35 to 44 | 18.5% | 16.5% | 12.9% |
| Age 45 to 54 | 13.7% | 12.8% | 12.6% |
| Age 55 to 59 | 3.6% | 6.5% | 6.7% |
| Age 60 to 64 | 3.6% | 5.4% | 6.3% |
| Age 65 to 74 | 5.7% | 6.8% | 9.6% |
| Age 75 to 84 | 1.9% | 2.9% | 4.5% |
| Age 85 and over | 0.4% | 0.4% | 1.9% |
| space1 | | | |
| Race | | | |
| | Stephens City, VA | Herndon, VA | United States |
| White | 63.9% | 35.4% | 59.4% |
| Black | 8.6% | 7.0% | 12.2% |
| Asian | 1.1% | 16.1% | 5.6% |
| Native American | 0.0% | 0.7% | 0.6% |
| Hawaiian, Pacific Islander | 1.0% | 0.0% | 0.2% |
| Other | 2.6% | 0.8% | 0.4% |
| Two or More Races | 3.9% | 3.3% | 3.2% |
| Hispanic | 18.9% | 36.7% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Stephens City, VA | Herndon, VA | United States |
| Married Population | 45.8% | 55.6% | 49.8% |
| Currently Married | 43.9% | 54.1% | 48.0% |
| Married but Separated | 1.9% | 1.5% | 1.8% |
| Single Population | 54.2% | 44.4% | 50.2% |
| Never Married | 35.2% | 34.8% | 33.8% |
| Divorced | 12.8% | 7.3% | 10.8% |
| Widowed | 6.1% | 2.3% | 5.6% |
| space5 | | | |
| Household Size | 2.88 | 3.10 | 2.60 |
| Households | 799 | 7,914 | 124,010,992 |
| Family Households | 504 | 5,747 | 80,755,759 |
| Married couple, w/children | 35.9% | 40.3% | 30.5% |
| Married couple, no children | 26.8% | 39.5% | 42.9% |
| Non Family Households | 295 | 2,167 | 43,255,233 |
| Single householder, w/children | 27.8% | 12.2% | 15.8% |
| Single householder, no children | 9.5% | 8.1% | 10.8% |