| | Okmulgee, OK | Ottawa, KS | United States |
| Population | 11,330 | 12,592 | 329,725,481 |
| Female Population | 51.7% | 50.5% | 50.5% |
| Male Population | 48.3% | 49.5% | 49.5% |
| Median Age | 35 | 35.5 | 38.4 |
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| Population - 2010 | 12,496 | 12,646 | 309,327,143 |
| Population - 2000 | 13,022 | 11,921 | 285,036,114 |
| Population - 1990 | 13,441 | 10,667 | 251,960,433 |
| Pop. 2000 to Now | -10.8% | 3.5% | 15.6% |
| Pop. 1990 to Now | -13.6% | 15.6% | 30.8% |
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| Population Density | 663.1 | 1,277.1 | 93.4 |
| Land Area | 17.1 | 9.9 | 3,531,905.4 |
| Water Area | 2.8 | 0.1 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Okmulgee, OK | Ottawa, KS | United States |
| Age 0 to 4 | 5.6% | 4.6% | 5.9% |
| Age 5 to 9 | 5.6% | 8.9% | 6.1% |
| Age 10 to 14 | 6.3% | 5.9% | 6.6% |
| Age 15 to 17 | 3.7% | 4.2% | 3.9% |
| Age 18 to 20 | 7.2% | 6.4% | 4.0% |
| Age 21 to 24 | 6.4% | 5.5% | 5.2% |
| Age 25 to 34 | 15.0% | 14.2% | 13.8% |
| Age 35 to 44 | 9.8% | 9.5% | 12.9% |
| Age 45 to 54 | 11.6% | 12.4% | 12.6% |
| Age 55 to 59 | 5.5% | 8.6% | 6.7% |
| Age 60 to 64 | 7.7% | 5.4% | 6.3% |
| Age 65 to 74 | 8.3% | 8.7% | 9.6% |
| Age 75 to 84 | 4.7% | 3.9% | 4.5% |
| Age 85 and over | 2.5% | 1.9% | 1.9% |
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| Race | | | |
| | Okmulgee, OK | Ottawa, KS | United States |
| White | 49.9% | 89.1% | 59.4% |
| Black | 17.3% | 0.8% | 12.2% |
| Asian | 1.3% | 0.7% | 5.6% |
| Native American | 16.8% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.3% | 0.0% | 0.4% |
| Two or More Races | 11.3% | 5.0% | 3.2% |
| Hispanic | 3.1% | 4.3% | 18.4% |
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| Marriage & Family | | | |
| | Okmulgee, OK | Ottawa, KS | United States |
| Married Population | 35.7% | 48.6% | 49.8% |
| Currently Married | 32.5% | 48.1% | 48.0% |
| Married but Separated | 3.2% | 0.5% | 1.8% |
| Single Population | 64.3% | 51.4% | 50.2% |
| Never Married | 40.1% | 31.9% | 33.8% |
| Divorced | 15.6% | 13.0% | 10.8% |
| Widowed | 8.6% | 6.5% | 5.6% |
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| Household Size | 2.37 | 2.43 | 2.60 |
| Households | 4,324 | 4,985 | 124,010,992 |
| Family Households | 2,548 | 3,221 | 80,755,759 |
| Married couple, w/children | 18.3% | 28.1% | 30.5% |
| Married couple, no children | 31.3% | 45.0% | 42.9% |
| Non Family Households | 1,776 | 1,764 | 43,255,233 |
| Single householder, w/children | 29.6% | 19.2% | 15.8% |
| Single householder, no children | 20.8% | 7.8% | 10.8% |