| | Union, WV | Montvale, VA | United States |
| Population | 435 | 402 | 329,725,481 |
| Female Population | 40.7% | 55.7% | 50.5% |
| Male Population | 59.3% | 44.3% | 49.5% |
| Median Age | 61.6 | 49.7 | 38.4 |
| space3 | | | |
| Population - 2010 | 565 | 841 | 309,327,143 |
| Population - 2000 | 548 | 733 | 285,036,114 |
| Population - 1990 | 566 | 760 | 251,960,433 |
| Pop. 2000 to Now | -1.6% | -43.9% | 15.6% |
| Pop. 1990 to Now | -4.8% | -45.9% | 30.8% |
| space4 | | | |
| Population Density | 973.2 | 166.5 | 93.4 |
| Land Area | 0.4 | 2.4 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Union, WV | Montvale, VA | United States |
| Age 0 to 4 | 2.1% | 0.0% | 5.9% |
| Age 5 to 9 | 1.4% | 9.2% | 6.1% |
| Age 10 to 14 | 0.9% | 0.0% | 6.6% |
| Age 15 to 17 | 0.9% | 5.5% | 3.9% |
| Age 18 to 20 | 1.6% | 10.2% | 4.0% |
| Age 21 to 24 | 1.1% | 2.5% | 5.2% |
| Age 25 to 34 | 9.7% | 10.9% | 13.8% |
| Age 35 to 44 | 9.7% | 11.2% | 12.9% |
| Age 45 to 54 | 12.4% | 7.2% | 12.6% |
| Age 55 to 59 | 9.0% | 13.9% | 6.7% |
| Age 60 to 64 | 10.1% | 8.5% | 6.3% |
| Age 65 to 74 | 20.5% | 4.2% | 9.6% |
| Age 75 to 84 | 18.9% | 16.7% | 4.5% |
| Age 85 and over | 1.8% | 0.0% | 1.9% |
| space1 | | | |
| Race | | | |
| | Union, WV | Montvale, VA | United States |
| White | 90.3% | 96.8% | 59.4% |
| Black | 0.7% | 0.0% | 12.2% |
| Asian | 0.0% | 0.0% | 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 | 2.3% | 3.2% | 3.2% |
| Hispanic | 6.7% | 0.0% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Union, WV | Montvale, VA | United States |
| Married Population | 43.3% | 23.8% | 49.8% |
| Currently Married | 43.3% | 23.8% | 48.0% |
| Married but Separated | 0.0% | 0.0% | 1.8% |
| Single Population | 56.7% | 76.2% | 50.2% |
| Never Married | 18.8% | 49.0% | 33.8% |
| Divorced | 29.3% | 17.0% | 10.8% |
| Widowed | 8.7% | 10.1% | 5.6% |
| space5 | | | |
| Household Size | 1.80 | 2.18 | 2.60 |
| Households | 242 | 184 | 124,010,992 |
| Family Households | 109 | 92 | 80,755,759 |
| Married couple, w/children | 5.5% | 22.8% | 30.5% |
| Married couple, no children | 74.3% | 23.9% | 42.9% |
| Non Family Households | 133 | 92 | 43,255,233 |
| Single householder, w/children | 10.1% | 27.2% | 15.8% |
| Single householder, no children | 10.1% | 26.1% | 10.8% |