| | Wellsville, PA | Seven Valleys, PA | United States |
| Population | 227 | 547 | 329,725,481 |
| Female Population | 47.1% | 49.9% | 50.5% |
| Male Population | 52.9% | 50.1% | 49.5% |
| Median Age | 41.3 | 33.3 | 38.4 |
| space3 | | | |
| Population - 2010 | 252 | 515 | 309,327,143 |
| Population - 2000 | 279 | 492 | 285,036,114 |
| Population - 1990 | 304 | 483 | 251,960,433 |
| Pop. 2000 to Now | -9.3% | 3.1% | 15.6% |
| Pop. 1990 to Now | -16.8% | 5.0% | 30.8% |
| space4 | | | |
| Population Density | 1,576.4 | 502.3 | 93.4 |
| Land Area | 0.1 | 1.1 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Wellsville, PA | Seven Valleys, PA | United States |
| Age 0 to 4 | 3.5% | 4.0% | 5.9% |
| Age 5 to 9 | 2.6% | 13.2% | 6.1% |
| Age 10 to 14 | 6.2% | 6.4% | 6.6% |
| Age 15 to 17 | 4.8% | 3.3% | 3.9% |
| Age 18 to 20 | 3.1% | 0.4% | 4.0% |
| Age 21 to 24 | 4.4% | 2.2% | 5.2% |
| Age 25 to 34 | 18.5% | 28.5% | 13.8% |
| Age 35 to 44 | 9.3% | 4.4% | 12.9% |
| Age 45 to 54 | 14.1% | 15.2% | 12.6% |
| Age 55 to 59 | 7.0% | 6.8% | 6.7% |
| Age 60 to 64 | 16.3% | 5.3% | 6.3% |
| Age 65 to 74 | 6.6% | 7.7% | 9.6% |
| Age 75 to 84 | 2.6% | 2.2% | 4.5% |
| Age 85 and over | 0.9% | 0.5% | 1.9% |
| space1 | | | |
| Race | | | |
| | Wellsville, PA | Seven Valleys, PA | United States |
| White | 98.7% | 99.3% | 59.4% |
| Black | 0.0% | 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 | 1.3% | 0.7% | 3.2% |
| Hispanic | 0.0% | 0.0% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Wellsville, PA | Seven Valleys, PA | United States |
| Married Population | 55.3% | 56.7% | 49.8% |
| Currently Married | 53.3% | 51.0% | 48.0% |
| Married but Separated | 2.0% | 5.7% | 1.8% |
| Single Population | 44.7% | 43.3% | 50.2% |
| Never Married | 28.1% | 20.8% | 33.8% |
| Divorced | 13.6% | 15.3% | 10.8% |
| Widowed | 3.0% | 7.2% | 5.6% |
| space5 | | | |
| Household Size | 2.36 | 2.19 | 2.60 |
| Households | 96 | 250 | 124,010,992 |
| Family Households | 60 | 136 | 80,755,759 |
| Married couple, w/children | 23.3% | 43.4% | 30.5% |
| Married couple, no children | 56.7% | 39.7% | 42.9% |
| Non Family Households | 36 | 114 | 43,255,233 |
| Single householder, w/children | 13.3% | 11.0% | 15.8% |
| Single householder, no children | 6.7% | 5.9% | 10.8% |