| | Glen Allen, VA | Onancock, VA | United States |
| Population | 14,783 | 1,291 | 329,725,481 |
| Female Population | 52.5% | 54.2% | 50.5% |
| Male Population | 47.5% | 45.8% | 49.5% |
| Median Age | 41 | 54.8 | 38.4 |
| space3 | | | |
| Population - 2010 | 15,580 | 1,260 | 309,327,143 |
| Population - 2000 | 12,562 | 1,525 | 285,036,114 |
| Population - 1990 | 9,010 | 1,434 | 251,960,433 |
| Pop. 2000 to Now | 33.8% | -21.0% | 15.6% |
| Pop. 1990 to Now | 86.6% | -16.0% | 30.8% |
| space4 | | | |
| Population Density | 1,680.3 | 1,233.1 | 93.4 |
| Land Area | 8.8 | 1.0 | 3,531,905.4 |
| Water Area | 0.1 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Glen Allen, VA | Onancock, VA | United States |
| Age 0 to 4 | 6.3% | 5.7% | 5.9% |
| Age 5 to 9 | 7.5% | 10.6% | 6.1% |
| Age 10 to 14 | 6.8% | 6.0% | 6.6% |
| Age 15 to 17 | 2.7% | 0.8% | 3.9% |
| Age 18 to 20 | 2.9% | 1.3% | 4.0% |
| Age 21 to 24 | 3.8% | 1.3% | 5.2% |
| Age 25 to 34 | 11.1% | 9.5% | 13.8% |
| Age 35 to 44 | 14.1% | 8.4% | 12.9% |
| Age 45 to 54 | 15.9% | 6.6% | 12.6% |
| Age 55 to 59 | 5.8% | 7.4% | 6.7% |
| Age 60 to 64 | 7.6% | 6.0% | 6.3% |
| Age 65 to 74 | 11.2% | 22.9% | 9.6% |
| Age 75 to 84 | 2.9% | 11.0% | 4.5% |
| Age 85 and over | 1.3% | 2.4% | 1.9% |
| space1 | | | |
| Race | | | |
| | Glen Allen, VA | Onancock, VA | United States |
| White | 58.6% | 48.5% | 59.4% |
| Black | 25.3% | 41.0% | 12.2% |
| Asian | 7.4% | 0.1% | 5.6% |
| Native American | 0.0% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.2% | 0.4% |
| Two or More Races | 2.2% | 5.5% | 3.2% |
| Hispanic | 6.4% | 4.7% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Glen Allen, VA | Onancock, VA | United States |
| Married Population | 53.4% | 48.0% | 49.8% |
| Currently Married | 51.6% | 45.7% | 48.0% |
| Married but Separated | 1.8% | 2.3% | 1.8% |
| Single Population | 46.6% | 52.0% | 50.2% |
| Never Married | 28.2% | 28.6% | 33.8% |
| Divorced | 13.8% | 13.9% | 10.8% |
| Widowed | 4.7% | 9.5% | 5.6% |
| space5 | | | |
| Household Size | 2.37 | 1.93 | 2.60 |
| Households | 6,218 | 666 | 124,010,992 |
| Family Households | 4,273 | 373 | 80,755,759 |
| Married couple, w/children | 29.1% | 11.8% | 30.5% |
| Married couple, no children | 40.2% | 53.1% | 42.9% |
| Non Family Households | 1,945 | 293 | 43,255,233 |
| Single householder, w/children | 18.0% | 28.2% | 15.8% |
| Single householder, no children | 12.8% | 7.0% | 10.8% |