| | Cleora, OK | Montgomery, IL | United States |
| Population | 1,425 | 20,084 | 329,725,481 |
| Female Population | 47.7% | 46.6% | 50.5% |
| Male Population | 52.4% | 53.4% | 49.5% |
| Median Age | 63 | 30.8 | 38.4 |
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| Population - 2010 | 1,478 | 18,385 | 309,327,143 |
| Population - 2000 | 1,113 | 5,471 | 285,036,114 |
| Population - 1990 | 909 | 4,267 | 251,960,433 |
| Pop. 2000 to Now | 30.2% | 268.9% | 15.6% |
| Pop. 1990 to Now | 59.4% | 373.0% | 30.8% |
| space4 | | | |
| Population Density | 120.2 | 2,168.9 | 93.4 |
| Land Area | 11.9 | 9.3 | 3,531,905.4 |
| Water Area | 0.3 | 0.2 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Cleora, OK | Montgomery, IL | United States |
| Age 0 to 4 | 2.1% | 6.3% | 5.9% |
| Age 5 to 9 | 0.8% | 7.6% | 6.1% |
| Age 10 to 14 | 3.5% | 9.2% | 6.6% |
| Age 15 to 17 | 0.6% | 8.4% | 3.9% |
| Age 18 to 20 | 3.9% | 5.6% | 4.0% |
| Age 21 to 24 | 0.5% | 5.5% | 5.2% |
| Age 25 to 34 | 3.5% | 13.0% | 13.8% |
| Age 35 to 44 | 6.0% | 17.0% | 12.9% |
| Age 45 to 54 | 9.4% | 11.9% | 12.6% |
| Age 55 to 59 | 12.6% | 5.7% | 6.7% |
| Age 60 to 64 | 9.1% | 3.3% | 6.3% |
| Age 65 to 74 | 30.3% | 3.8% | 9.6% |
| Age 75 to 84 | 16.2% | 2.0% | 4.5% |
| Age 85 and over | 1.5% | 0.6% | 1.9% |
| space1 | | | |
| Race | | | |
| | Cleora, OK | Montgomery, IL | United States |
| White | 78.9% | 64.6% | 59.4% |
| Black | 0.0% | 3.8% | 12.2% |
| Asian | 0.2% | 0.8% | 5.6% |
| Native American | 17.5% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.2% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 2.9% | 1.5% | 3.2% |
| Hispanic | 0.6% | 29.1% | 18.4% |
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| Marriage & Family | | | |
| | Cleora, OK | Montgomery, IL | United States |
| Married Population | 66.1% | 50.3% | 49.8% |
| Currently Married | 66.1% | 49.4% | 48.0% |
| Married but Separated | 0.0% | 0.9% | 1.8% |
| Single Population | 33.9% | 49.7% | 50.2% |
| Never Married | 12.4% | 37.5% | 33.8% |
| Divorced | 11.0% | 8.7% | 10.8% |
| Widowed | 10.5% | 3.6% | 5.6% |
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| Household Size | 1.85 | 3.14 | 2.60 |
| Households | 771 | 6,390 | 124,010,992 |
| Family Households | 543 | 4,679 | 80,755,759 |
| Married couple, w/children | 9.4% | 47.6% | 30.5% |
| Married couple, no children | 80.8% | 32.9% | 42.9% |
| Non Family Households | 228 | 1,711 | 43,255,233 |
| Single householder, w/children | 4.2% | 13.4% | 15.8% |
| Single householder, no children | 5.5% | 6.2% | 10.8% |