| | Hillsdale, MI | Mio, MI | United States |
| Population | 8,196 | 1,497 | 329,725,481 |
| Female Population | 50.8% | 51.7% | 50.5% |
| Male Population | 49.2% | 48.3% | 49.5% |
| Median Age | 29.6 | 43.1 | 38.4 |
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| Population - 2010 | 8,281 | 2,204 | 309,327,143 |
| Population - 2000 | 8,233 | 2,016 | 285,036,114 |
| Population - 1990 | 8,170 | 1,886 | 251,960,433 |
| Pop. 2000 to Now | -1.6% | -5.5% | 15.6% |
| Pop. 1990 to Now | -0.9% | 1.0% | 30.8% |
| space4 | | | |
| Population Density | 1,439.4 | 178.9 | 93.4 |
| Land Area | 5.7 | 8.4 | 3,531,905.4 |
| Water Area | 0.4 | 0.6 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Hillsdale, MI | Mio, MI | United States |
| Age 0 to 4 | 4.6% | 3.9% | 5.9% |
| Age 5 to 9 | 6.1% | 4.2% | 6.1% |
| Age 10 to 14 | 5.8% | 8.2% | 6.6% |
| Age 15 to 17 | 3.5% | 5.6% | 3.9% |
| Age 18 to 20 | 12.8% | 3.1% | 4.0% |
| Age 21 to 24 | 12.1% | 3.0% | 5.2% |
| Age 25 to 34 | 9.2% | 12.2% | 13.8% |
| Age 35 to 44 | 13.2% | 13.0% | 12.9% |
| Age 45 to 54 | 8.2% | 7.7% | 12.6% |
| Age 55 to 59 | 4.8% | 14.8% | 6.7% |
| Age 60 to 64 | 5.9% | 6.1% | 6.3% |
| Age 65 to 74 | 5.9% | 8.7% | 9.6% |
| Age 75 to 84 | 4.9% | 8.0% | 4.5% |
| Age 85 and over | 2.9% | 1.5% | 1.9% |
| space1 | | | |
| Race | | | |
| | Hillsdale, MI | Mio, MI | United States |
| White | 88.8% | 92.0% | 59.4% |
| Black | 1.3% | 1.1% | 12.2% |
| Asian | 0.6% | 0.2% | 5.6% |
| Native American | 0.1% | 0.5% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.4% | 0.0% | 0.4% |
| Two or More Races | 3.9% | 3.4% | 3.2% |
| Hispanic | 4.9% | 2.7% | 18.4% |
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| Marriage & Family | | | |
| | Hillsdale, MI | Mio, MI | United States |
| Married Population | 34.0% | 36.9% | 49.8% |
| Currently Married | 33.7% | 34.4% | 48.0% |
| Married but Separated | 0.3% | 2.5% | 1.8% |
| Single Population | 66.0% | 63.1% | 50.2% |
| Never Married | 46.0% | 36.6% | 33.8% |
| Divorced | 12.5% | 19.7% | 10.8% |
| Widowed | 7.5% | 6.8% | 5.6% |
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| Household Size | 2.36 | 2.49 | 2.60 |
| Households | 2,903 | 598 | 124,010,992 |
| Family Households | 1,547 | 372 | 80,755,759 |
| Married couple, w/children | 33.0% | 16.9% | 30.5% |
| Married couple, no children | 35.4% | 38.7% | 42.9% |
| Non Family Households | 1,356 | 226 | 43,255,233 |
| Single householder, w/children | 22.7% | 27.4% | 15.8% |
| Single householder, no children | 8.9% | 16.9% | 10.8% |