| | Warren, PA | Millsboro, DE | United States |
| Population | 9,363 | 6,542 | 329,725,481 |
| Female Population | 54.8% | 58.9% | 50.5% |
| Male Population | 45.2% | 41.1% | 49.5% |
| Median Age | 44.7 | 43.3 | 38.4 |
| space3 | | | |
| Population - 2010 | 9,700 | 3,871 | 309,327,143 |
| Population - 2000 | 10,259 | 2,360 | 285,036,114 |
| Population - 1990 | 11,122 | 1,643 | 251,960,433 |
| Pop. 2000 to Now | -12.5% | 97.7% | 15.6% |
| Pop. 1990 to Now | -19.3% | 183.9% | 30.8% |
| space4 | | | |
| Population Density | 3,216.4 | 1,761.0 | 93.4 |
| Land Area | 2.9 | 3.7 | 3,531,905.4 |
| Water Area | 0.2 | 0.2 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Warren, PA | Millsboro, DE | United States |
| Age 0 to 4 | 4.6% | 5.8% | 5.9% |
| Age 5 to 9 | 3.9% | 5.6% | 6.1% |
| Age 10 to 14 | 5.6% | 7.6% | 6.6% |
| Age 15 to 17 | 4.8% | 4.4% | 3.9% |
| Age 18 to 20 | 2.6% | 2.6% | 4.0% |
| Age 21 to 24 | 4.4% | 4.5% | 5.2% |
| Age 25 to 34 | 13.2% | 7.6% | 13.8% |
| Age 35 to 44 | 11.5% | 16.2% | 12.9% |
| Age 45 to 54 | 13.1% | 7.7% | 12.6% |
| Age 55 to 59 | 7.0% | 5.9% | 6.7% |
| Age 60 to 64 | 8.7% | 4.9% | 6.3% |
| Age 65 to 74 | 10.4% | 17.1% | 9.6% |
| Age 75 to 84 | 6.4% | 9.0% | 4.5% |
| Age 85 and over | 3.7% | 1.1% | 1.9% |
| space1 | | | |
| Race | | | |
| | Warren, PA | Millsboro, DE | United States |
| White | 95.0% | 76.0% | 59.4% |
| Black | 1.6% | 17.9% | 12.2% |
| Asian | 0.5% | 0.9% | 5.6% |
| Native American | 0.1% | 0.5% | 0.6% |
| Hawaiian, Pacific Islander | 0.1% | 0.0% | 0.2% |
| Other | 0.3% | 0.0% | 0.4% |
| Two or More Races | 1.4% | 4.1% | 3.2% |
| Hispanic | 1.0% | 0.7% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Warren, PA | Millsboro, DE | United States |
| Married Population | 43.2% | 55.4% | 49.8% |
| Currently Married | 41.1% | 52.9% | 48.0% |
| Married but Separated | 2.1% | 2.5% | 1.8% |
| Single Population | 56.8% | 44.6% | 50.2% |
| Never Married | 32.1% | 21.9% | 33.8% |
| Divorced | 18.2% | 10.5% | 10.8% |
| Widowed | 6.5% | 12.2% | 5.6% |
| space5 | | | |
| Household Size | 2.15 | 2.31 | 2.60 |
| Households | 4,241 | 2,758 | 124,010,992 |
| Family Households | 2,231 | 1,798 | 80,755,759 |
| Married couple, w/children | 21.6% | 28.1% | 30.5% |
| Married couple, no children | 47.8% | 42.2% | 42.9% |
| Non Family Households | 2,010 | 960 | 43,255,233 |
| Single householder, w/children | 20.9% | 21.6% | 15.8% |
| Single householder, no children | 9.7% | 8.1% | 10.8% |