| | Cyril, OK | Duncan, OK | United States |
| Population | 918 | 22,664 | 329,725,481 |
| Female Population | 49.0% | 51.9% | 50.5% |
| Male Population | 51.0% | 48.1% | 49.5% |
| Median Age | 30.3 | 38.7 | 38.4 |
| space3 | | | |
| Population - 2010 | 1,058 | 23,438 | 309,327,143 |
| Population - 2000 | 1,168 | 22,505 | 285,036,114 |
| Population - 1990 | 1,072 | 21,732 | 251,960,433 |
| Pop. 2000 to Now | -14.2% | -1.1% | 15.6% |
| Pop. 1990 to Now | -6.5% | 2.4% | 30.8% |
| space4 | | | |
| Population Density | 1,542.9 | 528.6 | 93.4 |
| Land Area | 0.6 | 42.9 | 3,531,905.4 |
| Water Area | 0.0 | 4.9 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Cyril, OK | Duncan, OK | United States |
| Age 0 to 4 | 10.5% | 6.8% | 5.9% |
| Age 5 to 9 | 8.3% | 6.7% | 6.1% |
| Age 10 to 14 | 9.4% | 6.5% | 6.6% |
| Age 15 to 17 | 2.1% | 3.9% | 3.9% |
| Age 18 to 20 | 2.8% | 3.9% | 4.0% |
| Age 21 to 24 | 8.9% | 4.1% | 5.2% |
| Age 25 to 34 | 13.7% | 13.5% | 13.8% |
| Age 35 to 44 | 10.8% | 11.6% | 12.9% |
| Age 45 to 54 | 6.0% | 11.5% | 12.6% |
| Age 55 to 59 | 9.0% | 6.3% | 6.7% |
| Age 60 to 64 | 5.0% | 6.6% | 6.3% |
| Age 65 to 74 | 4.4% | 11.1% | 9.6% |
| Age 75 to 84 | 7.0% | 4.9% | 4.5% |
| Age 85 and over | 2.2% | 2.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Cyril, OK | Duncan, OK | United States |
| White | 77.9% | 75.3% | 59.4% |
| Black | 0.0% | 2.5% | 12.2% |
| Asian | 0.0% | 0.7% | 5.6% |
| Native American | 2.9% | 3.6% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.1% | 0.2% |
| Other | 0.0% | 0.3% | 0.4% |
| Two or More Races | 12.7% | 6.3% | 3.2% |
| Hispanic | 6.4% | 11.1% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Cyril, OK | Duncan, OK | United States |
| Married Population | 54.2% | 51.3% | 49.8% |
| Currently Married | 47.9% | 49.5% | 48.0% |
| Married but Separated | 6.4% | 1.9% | 1.8% |
| Single Population | 45.8% | 48.7% | 50.2% |
| Never Married | 26.7% | 25.4% | 33.8% |
| Divorced | 9.5% | 14.0% | 10.8% |
| Widowed | 9.5% | 9.2% | 5.6% |
| space5 | | | |
| Household Size | 2.83 | 2.49 | 2.60 |
| Households | 324 | 8,938 | 124,010,992 |
| Family Households | 203 | 5,730 | 80,755,759 |
| Married couple, w/children | 38.4% | 29.9% | 30.5% |
| Married couple, no children | 36.5% | 43.4% | 42.9% |
| Non Family Households | 121 | 3,208 | 43,255,233 |
| Single householder, w/children | 14.8% | 17.6% | 15.8% |
| Single householder, no children | 10.3% | 9.1% | 10.8% |