| | Gallipolis, OH | Belpre, OH | United States |
| Population | 3,348 | 6,676 | 329,725,481 |
| Female Population | 51.6% | 51.6% | 50.5% |
| Male Population | 48.4% | 48.4% | 49.5% |
| Median Age | 41.5 | 44.8 | 38.4 |
| space3 | | | |
| Population - 2010 | 3,652 | 6,434 | 309,327,143 |
| Population - 2000 | 4,180 | 6,660 | 285,036,114 |
| Population - 1990 | 4,831 | 6,796 | 251,960,433 |
| Pop. 2000 to Now | -15.2% | -4.6% | 15.6% |
| Pop. 1990 to Now | -26.6% | -6.5% | 30.8% |
| space4 | | | |
| Population Density | 930.8 | 1,915.6 | 93.4 |
| Land Area | 3.6 | 3.5 | 3,531,905.4 |
| Water Area | 0.2 | 0.1 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Gallipolis, OH | Belpre, OH | United States |
| Age 0 to 4 | 9.8% | 5.7% | 5.9% |
| Age 5 to 9 | 6.8% | 4.6% | 6.1% |
| Age 10 to 14 | 3.4% | 4.9% | 6.6% |
| Age 15 to 17 | 1.0% | 3.9% | 3.9% |
| Age 18 to 20 | 1.6% | 2.3% | 4.0% |
| Age 21 to 24 | 5.1% | 5.8% | 5.2% |
| Age 25 to 34 | 18.5% | 13.6% | 13.8% |
| Age 35 to 44 | 4.3% | 9.7% | 12.9% |
| Age 45 to 54 | 8.3% | 12.0% | 12.6% |
| Age 55 to 59 | 4.8% | 7.3% | 6.7% |
| Age 60 to 64 | 8.9% | 7.1% | 6.3% |
| Age 65 to 74 | 15.2% | 14.1% | 9.6% |
| Age 75 to 84 | 9.8% | 6.8% | 4.5% |
| Age 85 and over | 2.6% | 2.4% | 1.9% |
| space1 | | | |
| Race | | | |
| | Gallipolis, OH | Belpre, OH | United States |
| White | 85.8% | 92.9% | 59.4% |
| Black | 4.1% | 1.0% | 12.2% |
| Asian | 2.4% | 0.6% | 5.6% |
| Native American | 0.0% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 2.7% | 3.3% | 3.2% |
| Hispanic | 5.0% | 2.3% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Gallipolis, OH | Belpre, OH | United States |
| Married Population | 43.0% | 43.8% | 49.8% |
| Currently Married | 41.2% | 43.5% | 48.0% |
| Married but Separated | 1.8% | 0.3% | 1.8% |
| Single Population | 57.0% | 56.2% | 50.2% |
| Never Married | 27.5% | 23.3% | 33.8% |
| Divorced | 13.8% | 25.3% | 10.8% |
| Widowed | 15.7% | 7.5% | 5.6% |
| space5 | | | |
| Household Size | 2.14 | 2.24 | 2.60 |
| Households | 1,521 | 2,978 | 124,010,992 |
| Family Households | 718 | 1,550 | 80,755,759 |
| Married couple, w/children | 26.0% | 29.3% | 30.5% |
| Married couple, no children | 46.7% | 45.2% | 42.9% |
| Non Family Households | 803 | 1,428 | 43,255,233 |
| Single householder, w/children | 10.0% | 17.5% | 15.8% |
| Single householder, no children | 17.3% | 8.0% | 10.8% |