| | Oglesby, IL | LaSalle, IL | United States |
| Population | 3,570 | 9,607 | 329,725,481 |
| Female Population | 47.8% | 52.3% | 50.5% |
| Male Population | 52.2% | 47.7% | 49.5% |
| Median Age | 40.3 | 38.5 | 38.4 |
| space3 | | | |
| Population - 2010 | 3,802 | 9,651 | 309,327,143 |
| Population - 2000 | 3,647 | 9,796 | 285,036,114 |
| Population - 1990 | 3,619 | 9,717 | 251,960,433 |
| Pop. 2000 to Now | -3.3% | -9.2% | 15.6% |
| Pop. 1990 to Now | -2.6% | -8.4% | 30.8% |
| space4 | | | |
| Population Density | 879.5 | 745.0 | 93.4 |
| Land Area | 4.1 | 12.9 | 3,531,905.4 |
| Water Area | 0.0 | 0.1 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Oglesby, IL | LaSalle, IL | United States |
| Age 0 to 4 | 4.0% | 6.9% | 5.9% |
| Age 5 to 9 | 9.7% | 5.7% | 6.1% |
| Age 10 to 14 | 6.5% | 6.3% | 6.6% |
| Age 15 to 17 | 4.4% | 3.5% | 3.9% |
| Age 18 to 20 | 3.4% | 4.4% | 4.0% |
| Age 21 to 24 | 2.4% | 4.3% | 5.2% |
| Age 25 to 34 | 13.4% | 15.0% | 13.8% |
| Age 35 to 44 | 10.2% | 11.1% | 12.9% |
| Age 45 to 54 | 12.4% | 10.7% | 12.6% |
| Age 55 to 59 | 9.7% | 7.8% | 6.7% |
| Age 60 to 64 | 4.9% | 5.1% | 6.3% |
| Age 65 to 74 | 10.2% | 9.9% | 9.6% |
| Age 75 to 84 | 5.1% | 6.7% | 4.5% |
| Age 85 and over | 3.8% | 2.6% | 1.9% |
| space1 | | | |
| Race | | | |
| | Oglesby, IL | LaSalle, IL | United States |
| White | 85.0% | 71.5% | 59.4% |
| Black | 0.0% | 1.6% | 12.2% |
| Asian | 0.0% | 1.5% | 5.6% |
| Native American | 0.2% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.5% | 0.4% |
| Two or More Races | 0.3% | 1.5% | 3.2% |
| Hispanic | 14.6% | 23.4% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Oglesby, IL | LaSalle, IL | United States |
| Married Population | 53.1% | 45.5% | 49.8% |
| Currently Married | 50.5% | 44.4% | 48.0% |
| Married but Separated | 2.5% | 1.1% | 1.8% |
| Single Population | 47.0% | 54.5% | 50.2% |
| Never Married | 30.7% | 34.2% | 33.8% |
| Divorced | 10.5% | 11.3% | 10.8% |
| Widowed | 5.7% | 9.0% | 5.6% |
| space5 | | | |
| Household Size | 2.34 | 2.29 | 2.60 |
| Households | 1,525 | 4,086 | 124,010,992 |
| Family Households | 964 | 2,479 | 80,755,759 |
| Married couple, w/children | 25.7% | 21.8% | 30.5% |
| Married couple, no children | 42.4% | 45.9% | 42.9% |
| Non Family Households | 561 | 1,607 | 43,255,233 |
| Single householder, w/children | 23.1% | 25.5% | 15.8% |
| Single householder, no children | 8.7% | 6.8% | 10.8% |