| | Miamisburg, OH | Eaton, OH | United States |
| Population | 19,878 | 8,355 | 329,725,481 |
| Female Population | 50.2% | 52.9% | 50.5% |
| Male Population | 49.8% | 47.1% | 49.5% |
| Median Age | 40 | 44.3 | 38.4 |
| space3 | | | |
| Population - 2010 | 20,166 | 8,388 | 309,327,143 |
| Population - 2000 | 19,489 | 8,133 | 285,036,114 |
| Population - 1990 | 17,834 | 7,396 | 251,960,433 |
| Pop. 2000 to Now | 3.2% | -0.1% | 15.6% |
| Pop. 1990 to Now | 12.8% | 9.8% | 30.8% |
| space4 | | | |
| Population Density | 1,629.8 | 1,332.5 | 93.4 |
| Land Area | 12.2 | 6.3 | 3,531,905.4 |
| Water Area | 0.2 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Miamisburg, OH | Eaton, OH | United States |
| Age 0 to 4 | 5.5% | 3.5% | 5.9% |
| Age 5 to 9 | 7.0% | 7.0% | 6.1% |
| Age 10 to 14 | 7.5% | 8.1% | 6.6% |
| Age 15 to 17 | 4.5% | 3.2% | 3.9% |
| Age 18 to 20 | 2.1% | 3.7% | 4.0% |
| Age 21 to 24 | 4.5% | 1.9% | 5.2% |
| Age 25 to 34 | 12.7% | 12.9% | 13.8% |
| Age 35 to 44 | 12.1% | 10.9% | 12.9% |
| Age 45 to 54 | 10.7% | 9.6% | 12.6% |
| Age 55 to 59 | 6.7% | 12.9% | 6.7% |
| Age 60 to 64 | 9.1% | 4.6% | 6.3% |
| Age 65 to 74 | 10.2% | 12.9% | 9.6% |
| Age 75 to 84 | 4.6% | 5.4% | 4.5% |
| Age 85 and over | 2.7% | 3.4% | 1.9% |
| space1 | | | |
| Race | | | |
| | Miamisburg, OH | Eaton, OH | United States |
| White | 92.4% | 94.0% | 59.4% |
| Black | 1.7% | 1.3% | 12.2% |
| Asian | 1.1% | 0.9% | 5.6% |
| Native American | 0.3% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.4% | 0.0% | 0.4% |
| Two or More Races | 2.1% | 2.8% | 3.2% |
| Hispanic | 1.8% | 0.9% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Miamisburg, OH | Eaton, OH | United States |
| Married Population | 56.1% | 45.7% | 49.8% |
| Currently Married | 55.1% | 45.1% | 48.0% |
| Married but Separated | 1.0% | 0.7% | 1.8% |
| Single Population | 43.9% | 54.3% | 50.2% |
| Never Married | 27.5% | 27.3% | 33.8% |
| Divorced | 9.7% | 15.7% | 10.8% |
| Widowed | 6.7% | 11.3% | 5.6% |
| space5 | | | |
| Household Size | 2.66 | 2.19 | 2.60 |
| Households | 7,378 | 3,683 | 124,010,992 |
| Family Households | 5,292 | 1,865 | 80,755,759 |
| Married couple, w/children | 35.3% | 39.1% | 30.5% |
| Married couple, no children | 42.9% | 38.6% | 42.9% |
| Non Family Households | 2,086 | 1,818 | 43,255,233 |
| Single householder, w/children | 14.2% | 14.9% | 15.8% |
| Single householder, no children | 7.6% | 7.4% | 10.8% |