| | Dallas, GA | Belvidere, IL | United States |
| Population | 13,704 | 25,179 | 329,725,481 |
| Female Population | 57.2% | 52.3% | 50.5% |
| Male Population | 42.8% | 47.7% | 49.5% |
| Median Age | 32.9 | 36.9 | 38.4 |
| space3 | | | |
| Population - 2010 | 11,577 | 25,598 | 309,327,143 |
| Population - 2000 | 5,056 | 20,820 | 285,036,114 |
| Population - 1990 | 2,810 | 15,958 | 251,960,433 |
| Pop. 2000 to Now | 184.6% | 18.8% | 15.6% |
| Pop. 1990 to Now | 412.0% | 55.0% | 30.8% |
| space4 | | | |
| Population Density | 1,856.7 | 2,085.9 | 93.4 |
| Land Area | 7.4 | 12.1 | 3,531,905.4 |
| Water Area | 0.0 | 0.2 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Dallas, GA | Belvidere, IL | United States |
| Age 0 to 4 | 12.1% | 5.9% | 5.9% |
| Age 5 to 9 | 3.2% | 7.1% | 6.1% |
| Age 10 to 14 | 7.1% | 7.2% | 6.6% |
| Age 15 to 17 | 6.1% | 3.6% | 3.9% |
| Age 18 to 20 | 4.3% | 4.5% | 4.0% |
| Age 21 to 24 | 7.3% | 4.5% | 5.2% |
| Age 25 to 34 | 13.6% | 13.4% | 13.8% |
| Age 35 to 44 | 13.7% | 11.9% | 12.9% |
| Age 45 to 54 | 15.9% | 13.5% | 12.6% |
| Age 55 to 59 | 3.1% | 7.5% | 6.7% |
| Age 60 to 64 | 3.9% | 4.8% | 6.3% |
| Age 65 to 74 | 4.6% | 10.1% | 9.6% |
| Age 75 to 84 | 3.2% | 4.4% | 4.5% |
| Age 85 and over | 1.9% | 1.4% | 1.9% |
| space1 | | | |
| Race | | | |
| | Dallas, GA | Belvidere, IL | United States |
| White | 50.8% | 60.1% | 59.4% |
| Black | 29.5% | 1.3% | 12.2% |
| Asian | 1.4% | 0.9% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 1.5% | 0.2% | 0.4% |
| Two or More Races | 6.2% | 1.1% | 3.2% |
| Hispanic | 10.6% | 36.4% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Dallas, GA | Belvidere, IL | United States |
| Married Population | 43.7% | 42.0% | 49.8% |
| Currently Married | 43.1% | 39.9% | 48.0% |
| Married but Separated | 0.6% | 2.1% | 1.8% |
| Single Population | 56.3% | 58.0% | 50.2% |
| Never Married | 32.1% | 36.6% | 33.8% |
| Divorced | 18.7% | 14.5% | 10.8% |
| Widowed | 5.5% | 6.9% | 5.6% |
| space5 | | | |
| Household Size | 2.57 | 2.71 | 2.60 |
| Households | 5,269 | 9,193 | 124,010,992 |
| Family Households | 3,507 | 5,829 | 80,755,759 |
| Married couple, w/children | 40.5% | 26.5% | 30.5% |
| Married couple, no children | 20.7% | 37.6% | 42.9% |
| Non Family Households | 1,762 | 3,364 | 43,255,233 |
| Single householder, w/children | 33.2% | 23.0% | 15.8% |
| Single householder, no children | 5.6% | 12.9% | 10.8% |