| | Fort Riley, KS | Columbus, GA | United States |
| Population | 8,006 | 204,366 | 329,725,481 |
| Female Population | 35.7% | 51.2% | 50.5% |
| Male Population | 64.3% | 48.8% | 49.5% |
| Median Age | 22.6 | 34.6 | 38.4 |
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| Population - 2010 | 8,423 | 191,122 | 309,327,143 |
| Population - 2000 | 6,958 | 184,652 | 285,036,114 |
| Population - 1990 | 12,050 | 178,069 | 251,960,433 |
| Pop. 2000 to Now | 6.3% | 6.4% | 15.6% |
| Pop. 1990 to Now | -38.6% | 10.3% | 30.8% |
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| Population Density | 1,568.0 | 944.2 | 93.4 |
| Land Area | 5.1 | 216.4 | 3,531,905.4 |
| Water Area | 0.0 | 4.6 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Fort Riley, KS | Columbus, GA | United States |
| Age 0 to 4 | 14.0% | 7.1% | 5.9% |
| Age 5 to 9 | 4.7% | 7.1% | 6.1% |
| Age 10 to 14 | 2.8% | 7.0% | 6.6% |
| Age 15 to 17 | 0.8% | 3.8% | 3.9% |
| Age 18 to 20 | 12.4% | 4.2% | 4.0% |
| Age 21 to 24 | 31.9% | 5.5% | 5.2% |
| Age 25 to 34 | 25.5% | 16.0% | 13.8% |
| Age 35 to 44 | 6.8% | 12.9% | 12.9% |
| Age 45 to 54 | 0.5% | 11.3% | 12.6% |
| Age 55 to 59 | 0.2% | 5.7% | 6.7% |
| Age 60 to 64 | 0.4% | 5.9% | 6.3% |
| Age 65 to 74 | 0.0% | 8.1% | 9.6% |
| Age 75 to 84 | 0.0% | 3.5% | 4.5% |
| Age 85 and over | 0.0% | 1.8% | 1.9% |
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| Race | | | |
| | Fort Riley, KS | Columbus, GA | United States |
| White | 56.5% | 39.2% | 59.4% |
| Black | 16.1% | 45.4% | 12.2% |
| Asian | 2.0% | 2.6% | 5.6% |
| Native American | 0.1% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.1% | 0.1% | 0.2% |
| Other | 0.0% | 0.4% | 0.4% |
| Two or More Races | 4.3% | 4.3% | 3.2% |
| Hispanic | 21.0% | 7.9% | 18.4% |
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| Marriage & Family | | | |
| | Fort Riley, KS | Columbus, GA | United States |
| Married Population | 53.5% | 42.1% | 49.8% |
| Currently Married | 52.3% | 39.0% | 48.0% |
| Married but Separated | 1.2% | 3.2% | 1.8% |
| Single Population | 46.5% | 57.9% | 50.2% |
| Never Married | 45.5% | 38.0% | 33.8% |
| Divorced | 0.7% | 13.5% | 10.8% |
| Widowed | 0.3% | 6.4% | 5.6% |
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| Household Size | 2.77 | 2.52 | 2.60 |
| Households | 1,911 | 78,491 | 124,010,992 |
| Family Households | 1,637 | 47,216 | 80,755,759 |
| Married couple, w/children | 55.3% | 24.6% | 30.5% |
| Married couple, no children | 35.9% | 35.2% | 42.9% |
| Non Family Households | 274 | 31,275 | 43,255,233 |
| Single householder, w/children | 8.8% | 26.9% | 15.8% |
| Single householder, no children | 0.0% | 13.2% | 10.8% |