| | Ottawa, KS | Independence, KS | United States |
| Population | 12,592 | 8,584 | 329,725,481 |
| Female Population | 50.5% | 49.7% | 50.5% |
| Male Population | 49.5% | 50.3% | 49.5% |
| Median Age | 35.5 | 38.4 | 38.4 |
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| Population - 2010 | 12,646 | 9,466 | 309,327,143 |
| Population - 2000 | 11,921 | 9,846 | 285,036,114 |
| Population - 1990 | 10,667 | 9,942 | 251,960,433 |
| Pop. 2000 to Now | 3.5% | -14.4% | 15.6% |
| Pop. 1990 to Now | 15.6% | -15.3% | 30.8% |
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| Population Density | 1,277.1 | 1,119.8 | 93.4 |
| Land Area | 9.9 | 7.7 | 3,531,905.4 |
| Water Area | 0.1 | 0.0 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Ottawa, KS | Independence, KS | United States |
| Age 0 to 4 | 4.6% | 5.2% | 5.9% |
| Age 5 to 9 | 8.9% | 7.4% | 6.1% |
| Age 10 to 14 | 5.9% | 7.1% | 6.6% |
| Age 15 to 17 | 4.2% | 3.7% | 3.9% |
| Age 18 to 20 | 6.4% | 2.9% | 4.0% |
| Age 21 to 24 | 5.5% | 6.1% | 5.2% |
| Age 25 to 34 | 14.2% | 13.2% | 13.8% |
| Age 35 to 44 | 9.5% | 10.5% | 12.9% |
| Age 45 to 54 | 12.4% | 10.5% | 12.6% |
| Age 55 to 59 | 8.6% | 6.4% | 6.7% |
| Age 60 to 64 | 5.4% | 8.4% | 6.3% |
| Age 65 to 74 | 8.7% | 10.6% | 9.6% |
| Age 75 to 84 | 3.9% | 5.3% | 4.5% |
| Age 85 and over | 1.9% | 2.8% | 1.9% |
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| Race | | | |
| | Ottawa, KS | Independence, KS | United States |
| White | 89.1% | 80.5% | 59.4% |
| Black | 0.8% | 5.0% | 12.2% |
| Asian | 0.7% | 0.2% | 5.6% |
| Native American | 0.0% | 0.9% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.5% | 0.4% |
| Two or More Races | 5.0% | 5.0% | 3.2% |
| Hispanic | 4.3% | 7.9% | 18.4% |
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| Marriage & Family | | | |
| | Ottawa, KS | Independence, KS | United States |
| Married Population | 48.6% | 43.3% | 49.8% |
| Currently Married | 48.1% | 42.5% | 48.0% |
| Married but Separated | 0.5% | 0.9% | 1.8% |
| Single Population | 51.4% | 56.7% | 50.2% |
| Never Married | 31.9% | 31.0% | 33.8% |
| Divorced | 13.0% | 16.0% | 10.8% |
| Widowed | 6.5% | 9.6% | 5.6% |
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| Household Size | 2.43 | 2.21 | 2.60 |
| Households | 4,985 | 3,796 | 124,010,992 |
| Family Households | 3,221 | 2,120 | 80,755,759 |
| Married couple, w/children | 28.1% | 21.3% | 30.5% |
| Married couple, no children | 45.0% | 43.9% | 42.9% |
| Non Family Households | 1,764 | 1,676 | 43,255,233 |
| Single householder, w/children | 19.2% | 21.1% | 15.8% |
| Single householder, no children | 7.8% | 13.7% | 10.8% |