| | Duncan, AZ | Douglas, AZ | United States |
| Population | 787 | 16,470 | 329,725,481 |
| Female Population | 50.3% | 40.9% | 50.5% |
| Male Population | 49.7% | 59.1% | 49.5% |
| Median Age | 31.1 | 32.9 | 38.4 |
| space3 | | | |
| Population - 2010 | 689 | 17,606 | 309,327,143 |
| Population - 2000 | 812 | 14,312 | 285,036,114 |
| Population - 1990 | 662 | 12,822 | 251,960,433 |
| Pop. 2000 to Now | -4.7% | 15.0% | 15.6% |
| Pop. 1990 to Now | 16.9% | 28.4% | 30.8% |
| space4 | | | |
| Population Density | 365.7 | 1,648.5 | 93.4 |
| Land Area | 2.2 | 10.0 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Duncan, AZ | Douglas, AZ | United States |
| Age 0 to 4 | 12.2% | 8.0% | 5.9% |
| Age 5 to 9 | 5.8% | 5.7% | 6.1% |
| Age 10 to 14 | 10.2% | 5.1% | 6.6% |
| Age 15 to 17 | 9.0% | 4.0% | 3.9% |
| Age 18 to 20 | 4.1% | 5.8% | 4.0% |
| Age 21 to 24 | 5.8% | 5.9% | 5.2% |
| Age 25 to 34 | 5.1% | 19.4% | 13.8% |
| Age 35 to 44 | 14.9% | 13.7% | 12.9% |
| Age 45 to 54 | 9.9% | 9.8% | 12.6% |
| Age 55 to 59 | 3.6% | 5.4% | 6.7% |
| Age 60 to 64 | 5.1% | 4.9% | 6.3% |
| Age 65 to 74 | 7.6% | 7.4% | 9.6% |
| Age 75 to 84 | 5.7% | 3.9% | 4.5% |
| Age 85 and over | 1.0% | 1.0% | 1.9% |
| space1 | | | |
| Race | | | |
| | Duncan, AZ | Douglas, AZ | United States |
| White | 67.0% | 11.6% | 59.4% |
| Black | 0.0% | 3.5% | 12.2% |
| Asian | 0.0% | 0.1% | 5.6% |
| Native American | 0.4% | 0.9% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.1% | 0.2% |
| Other | 0.0% | 0.1% | 0.4% |
| Two or More Races | 1.5% | 0.8% | 3.2% |
| Hispanic | 31.1% | 82.7% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Duncan, AZ | Douglas, AZ | United States |
| Married Population | 47.8% | 37.2% | 49.8% |
| Currently Married | 41.4% | 34.4% | 48.0% |
| Married but Separated | 6.4% | 2.8% | 1.8% |
| Single Population | 52.2% | 62.8% | 50.2% |
| Never Married | 29.6% | 45.6% | 33.8% |
| Divorced | 14.3% | 11.8% | 10.8% |
| Widowed | 8.3% | 5.4% | 5.6% |
| space5 | | | |
| Household Size | 2.87 | 2.93 | 2.60 |
| Households | 274 | 4,446 | 124,010,992 |
| Family Households | 183 | 3,080 | 80,755,759 |
| Married couple, w/children | 29.0% | 31.2% | 30.5% |
| Married couple, no children | 33.3% | 31.7% | 42.9% |
| Non Family Households | 91 | 1,366 | 43,255,233 |
| Single householder, w/children | 26.8% | 27.2% | 15.8% |
| Single householder, no children | 10.9% | 9.8% | 10.8% |