| | Mariemont, OH | Worthington, OH | United States |
| Population | 3,497 | 15,047 | 329,725,481 |
| Female Population | 51.6% | 52.8% | 50.5% |
| Male Population | 48.4% | 47.2% | 49.5% |
| Median Age | 39.7 | 40.7 | 38.4 |
| space3 | | | |
| Population - 2010 | 3,399 | 13,582 | 309,327,143 |
| Population - 2000 | 3,408 | 14,125 | 285,036,114 |
| Population - 1990 | 3,118 | 14,869 | 251,960,433 |
| Pop. 2000 to Now | 0.9% | 4.5% | 15.6% |
| Pop. 1990 to Now | 10.3% | -0.7% | 30.8% |
| space4 | | | |
| Population Density | 3,889.9 | 2,750.8 | 93.4 |
| Land Area | 0.9 | 5.5 | 3,531,905.4 |
| Water Area | 0.0 | 0.1 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Mariemont, OH | Worthington, OH | United States |
| Age 0 to 4 | 5.3% | 7.6% | 5.9% |
| Age 5 to 9 | 5.9% | 7.3% | 6.1% |
| Age 10 to 14 | 7.1% | 7.2% | 6.6% |
| Age 15 to 17 | 5.7% | 3.2% | 3.9% |
| Age 18 to 20 | 4.0% | 1.7% | 4.0% |
| Age 21 to 24 | 2.0% | 2.1% | 5.2% |
| Age 25 to 34 | 12.3% | 10.3% | 13.8% |
| Age 35 to 44 | 15.9% | 16.7% | 12.9% |
| Age 45 to 54 | 15.0% | 11.6% | 12.6% |
| Age 55 to 59 | 3.3% | 5.7% | 6.7% |
| Age 60 to 64 | 6.5% | 5.9% | 6.3% |
| Age 65 to 74 | 9.0% | 12.5% | 9.6% |
| Age 75 to 84 | 6.5% | 4.4% | 4.5% |
| Age 85 and over | 1.3% | 4.0% | 1.9% |
| space1 | | | |
| Race | | | |
| | Mariemont, OH | Worthington, OH | United States |
| White | 95.8% | 90.1% | 59.4% |
| Black | 2.3% | 3.1% | 12.2% |
| Asian | 0.9% | 2.6% | 5.6% |
| Native American | 0.2% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 0.7% | 2.4% | 3.2% |
| Hispanic | 0.2% | 1.8% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Mariemont, OH | Worthington, OH | United States |
| Married Population | 58.8% | 63.4% | 49.8% |
| Currently Married | 58.1% | 62.3% | 48.0% |
| Married but Separated | 0.7% | 1.1% | 1.8% |
| Single Population | 41.2% | 36.6% | 50.2% |
| Never Married | 26.7% | 20.0% | 33.8% |
| Divorced | 11.1% | 9.4% | 10.8% |
| Widowed | 3.4% | 7.2% | 5.6% |
| space5 | | | |
| Household Size | 2.36 | 2.46 | 2.60 |
| Households | 1,469 | 6,030 | 124,010,992 |
| Family Households | 877 | 4,132 | 80,755,759 |
| Married couple, w/children | 44.5% | 40.4% | 30.5% |
| Married couple, no children | 47.5% | 43.0% | 42.9% |
| Non Family Households | 592 | 1,898 | 43,255,233 |
| Single householder, w/children | 5.6% | 9.0% | 15.8% |
| Single householder, no children | 2.4% | 7.6% | 10.8% |