| | Oglesby, IL | Clarksville, AR | United States |
| Population | 3,570 | 9,444 | 329,725,481 |
| Female Population | 47.8% | 46.4% | 50.5% |
| Male Population | 52.2% | 53.6% | 49.5% |
| Median Age | 40.3 | 34.4 | 38.4 |
| space3 | | | |
| Population - 2010 | 3,802 | 9,201 | 309,327,143 |
| Population - 2000 | 3,647 | 7,719 | 285,036,114 |
| Population - 1990 | 3,619 | 5,833 | 251,960,433 |
| Pop. 2000 to Now | -3.3% | 25.9% | 15.6% |
| Pop. 1990 to Now | -2.6% | 66.7% | 30.8% |
| space4 | | | |
| Population Density | 879.5 | 510.3 | 93.4 |
| Land Area | 4.1 | 18.5 | 3,531,905.4 |
| Water Area | 0.0 | 0.6 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Oglesby, IL | Clarksville, AR | United States |
| Age 0 to 4 | 4.0% | 6.4% | 5.9% |
| Age 5 to 9 | 9.7% | 5.6% | 6.1% |
| Age 10 to 14 | 6.5% | 5.4% | 6.6% |
| Age 15 to 17 | 4.4% | 3.9% | 3.9% |
| Age 18 to 20 | 3.4% | 6.9% | 4.0% |
| Age 21 to 24 | 2.4% | 9.4% | 5.2% |
| Age 25 to 34 | 13.4% | 13.7% | 13.8% |
| Age 35 to 44 | 10.2% | 7.9% | 12.9% |
| Age 45 to 54 | 12.4% | 11.1% | 12.6% |
| Age 55 to 59 | 9.7% | 7.9% | 6.7% |
| Age 60 to 64 | 4.9% | 4.9% | 6.3% |
| Age 65 to 74 | 10.2% | 8.8% | 9.6% |
| Age 75 to 84 | 5.1% | 6.5% | 4.5% |
| Age 85 and over | 3.8% | 1.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Oglesby, IL | Clarksville, AR | United States |
| White | 85.0% | 60.7% | 59.4% |
| Black | 0.0% | 3.9% | 12.2% |
| Asian | 0.0% | 5.1% | 5.6% |
| Native American | 0.2% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.1% | 0.2% |
| Other | 0.0% | 0.9% | 0.4% |
| Two or More Races | 0.3% | 4.0% | 3.2% |
| Hispanic | 14.6% | 25.4% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Oglesby, IL | Clarksville, AR | United States |
| Married Population | 53.1% | 42.3% | 49.8% |
| Currently Married | 50.5% | 39.6% | 48.0% |
| Married but Separated | 2.5% | 2.7% | 1.8% |
| Single Population | 47.0% | 57.7% | 50.2% |
| Never Married | 30.7% | 35.6% | 33.8% |
| Divorced | 10.5% | 17.4% | 10.8% |
| Widowed | 5.7% | 4.6% | 5.6% |
| space5 | | | |
| Household Size | 2.34 | 2.37 | 2.60 |
| Households | 1,525 | 3,691 | 124,010,992 |
| Family Households | 964 | 2,148 | 80,755,759 |
| Married couple, w/children | 25.7% | 22.3% | 30.5% |
| Married couple, no children | 42.4% | 44.7% | 42.9% |
| Non Family Households | 561 | 1,543 | 43,255,233 |
| Single householder, w/children | 23.1% | 23.6% | 15.8% |
| Single householder, no children | 8.7% | 9.4% | 10.8% |