| | Greenville, PA | Oil City, PA | United States |
| Population | 5,578 | 9,685 | 329,725,481 |
| Female Population | 52.9% | 49.4% | 50.5% |
| Male Population | 47.1% | 50.6% | 49.5% |
| Median Age | 28.5 | 41.3 | 38.4 |
| space3 | | | |
| Population - 2010 | 5,947 | 10,540 | 309,327,143 |
| Population - 2000 | 6,380 | 11,504 | 285,036,114 |
| Population - 1990 | 6,734 | 11,949 | 251,960,433 |
| Pop. 2000 to Now | -18.9% | -17.1% | 15.6% |
| Pop. 1990 to Now | -23.1% | -20.1% | 30.8% |
| space4 | | | |
| Population Density | 2,956.0 | 2,155.6 | 93.4 |
| Land Area | 1.9 | 4.5 | 3,531,905.4 |
| Water Area | 0.0 | 0.3 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Greenville, PA | Oil City, PA | United States |
| Age 0 to 4 | 11.0% | 4.3% | 5.9% |
| Age 5 to 9 | 7.0% | 6.3% | 6.1% |
| Age 10 to 14 | 3.2% | 6.1% | 6.6% |
| Age 15 to 17 | 2.7% | 5.5% | 3.9% |
| Age 18 to 20 | 11.2% | 3.4% | 4.0% |
| Age 21 to 24 | 10.1% | 4.5% | 5.2% |
| Age 25 to 34 | 12.7% | 11.8% | 13.8% |
| Age 35 to 44 | 10.5% | 12.6% | 12.9% |
| Age 45 to 54 | 9.4% | 13.7% | 12.6% |
| Age 55 to 59 | 4.4% | 4.8% | 6.7% |
| Age 60 to 64 | 5.2% | 8.7% | 6.3% |
| Age 65 to 74 | 7.2% | 11.0% | 9.6% |
| Age 75 to 84 | 3.3% | 5.4% | 4.5% |
| Age 85 and over | 1.9% | 1.9% | 1.9% |
| space1 | | | |
| Race | | | |
| | Greenville, PA | Oil City, PA | United States |
| White | 93.6% | 94.2% | 59.4% |
| Black | 1.3% | 1.2% | 12.2% |
| Asian | 0.6% | 0.1% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.1% | 0.0% | 0.4% |
| Two or More Races | 2.5% | 2.5% | 3.2% |
| Hispanic | 1.8% | 2.1% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Greenville, PA | Oil City, PA | United States |
| Married Population | 43.5% | 45.2% | 49.8% |
| Currently Married | 38.1% | 42.2% | 48.0% |
| Married but Separated | 5.4% | 3.0% | 1.8% |
| Single Population | 56.5% | 54.8% | 50.2% |
| Never Married | 39.4% | 30.9% | 33.8% |
| Divorced | 11.5% | 17.7% | 10.8% |
| Widowed | 5.6% | 6.2% | 5.6% |
| space5 | | | |
| Household Size | 2.47 | 2.34 | 2.60 |
| Households | 1,941 | 4,019 | 124,010,992 |
| Family Households | 1,158 | 2,285 | 80,755,759 |
| Married couple, w/children | 35.2% | 34.1% | 30.5% |
| Married couple, no children | 35.7% | 36.5% | 42.9% |
| Non Family Households | 783 | 1,734 | 43,255,233 |
| Single householder, w/children | 21.8% | 19.6% | 15.8% |
| Single householder, no children | 7.3% | 9.8% | 10.8% |