| | Grassflat, PA | DuBois, PA | United States |
| Population | 505 | 7,548 | 329,725,481 |
| Female Population | 50.5% | 51.5% | 50.5% |
| Male Population | 49.5% | 48.5% | 49.5% |
| Median Age | 31.6 | 39.7 | 38.4 |
| space3 | | | |
| Population - 2010 | 504 | 7,778 | 309,327,143 |
| Population - 2000 | 509 | 8,123 | 285,036,114 |
| Population - 1990 | 477 | 8,286 | 251,960,433 |
| Pop. 2000 to Now | 43.8% | -10.3% | 15.6% |
| Pop. 1990 to Now | 53.5% | -12.1% | 30.8% |
| space4 | | | |
| Population Density | 446.5 | 2,375.8 | 93.4 |
| Land Area | 1.1 | 3.2 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Grassflat, PA | DuBois, PA | United States |
| Age 0 to 4 | 5.0% | 3.9% | 5.9% |
| Age 5 to 9 | 10.1% | 5.3% | 6.1% |
| Age 10 to 14 | 15.4% | 5.4% | 6.6% |
| Age 15 to 17 | 0.6% | 4.7% | 3.9% |
| Age 18 to 20 | 7.3% | 2.2% | 4.0% |
| Age 21 to 24 | 2.4% | 5.9% | 5.2% |
| Age 25 to 34 | 12.5% | 17.5% | 13.8% |
| Age 35 to 44 | 21.6% | 9.4% | 12.9% |
| Age 45 to 54 | 14.5% | 9.9% | 12.6% |
| Age 55 to 59 | 4.8% | 7.2% | 6.7% |
| Age 60 to 64 | 1.8% | 8.0% | 6.3% |
| Age 65 to 74 | 0.8% | 11.8% | 9.6% |
| Age 75 to 84 | 3.4% | 5.6% | 4.5% |
| Age 85 and over | 0.0% | 3.0% | 1.9% |
| space1 | | | |
| Race | | | |
| | Grassflat, PA | DuBois, PA | United States |
| White | 100.0% | 96.6% | 59.4% |
| Black | 0.0% | 0.8% | 12.2% |
| Asian | 0.0% | 0.5% | 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 | 0.0% | 0.4% | 3.2% |
| Hispanic | 0.0% | 1.7% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Grassflat, PA | DuBois, PA | United States |
| Married Population | 51.6% | 38.3% | 49.8% |
| Currently Married | 51.6% | 36.3% | 48.0% |
| Married but Separated | 0.0% | 2.1% | 1.8% |
| Single Population | 48.4% | 61.7% | 50.2% |
| Never Married | 33.3% | 35.7% | 33.8% |
| Divorced | 9.4% | 15.2% | 10.8% |
| Widowed | 5.7% | 10.8% | 5.6% |
| space5 | | | |
| Household Size | 3.30 | 2.11 | 2.60 |
| Households | 153 | 3,531 | 124,010,992 |
| Family Households | 122 | 1,732 | 80,755,759 |
| Married couple, w/children | 51.6% | 20.6% | 30.5% |
| Married couple, no children | 23.8% | 42.2% | 42.9% |
| Non Family Households | 31 | 1,799 | 43,255,233 |
| Single householder, w/children | 9.8% | 24.4% | 15.8% |
| Single householder, no children | 14.8% | 12.8% | 10.8% |