| | Holly, MI | Caro, MI | United States |
| Population | 6,031 | 4,318 | 329,725,481 |
| Female Population | 54.4% | 48.8% | 50.5% |
| Male Population | 45.6% | 51.2% | 49.5% |
| Median Age | 44.4 | 42.6 | 38.4 |
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| Population - 2010 | 6,076 | 4,268 | 309,327,143 |
| Population - 2000 | 6,135 | 4,145 | 285,036,114 |
| Population - 1990 | 5,595 | 4,054 | 251,960,433 |
| Pop. 2000 to Now | -0.9% | -3.7% | 15.6% |
| Pop. 1990 to Now | 8.7% | -1.5% | 30.8% |
| space4 | | | |
| Population Density | 2,220.5 | 1,505.6 | 93.4 |
| Land Area | 2.7 | 2.9 | 3,531,905.4 |
| Water Area | 0.3 | 0.0 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Holly, MI | Caro, MI | United States |
| Age 0 to 4 | 4.5% | 4.6% | 5.9% |
| Age 5 to 9 | 6.4% | 7.1% | 6.1% |
| Age 10 to 14 | 5.4% | 6.4% | 6.6% |
| Age 15 to 17 | 1.7% | 3.2% | 3.9% |
| Age 18 to 20 | 2.3% | 4.0% | 4.0% |
| Age 21 to 24 | 4.4% | 5.8% | 5.2% |
| Age 25 to 34 | 11.7% | 11.0% | 13.8% |
| Age 35 to 44 | 14.5% | 11.1% | 12.9% |
| Age 45 to 54 | 16.7% | 13.8% | 12.6% |
| Age 55 to 59 | 7.5% | 5.4% | 6.7% |
| Age 60 to 64 | 7.5% | 5.4% | 6.3% |
| Age 65 to 74 | 8.6% | 11.8% | 9.6% |
| Age 75 to 84 | 4.0% | 6.0% | 4.5% |
| Age 85 and over | 4.9% | 4.3% | 1.9% |
| space1 | | | |
| Race | | | |
| | Holly, MI | Caro, MI | United States |
| White | 90.0% | 92.1% | 59.4% |
| Black | 1.8% | 1.4% | 12.2% |
| Asian | 0.0% | 0.0% | 5.6% |
| Native American | 0.2% | 0.6% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 5.5% | 1.6% | 3.2% |
| Hispanic | 2.6% | 4.4% | 18.4% |
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| Marriage & Family | | | |
| | Holly, MI | Caro, MI | United States |
| Married Population | 45.7% | 33.6% | 49.8% |
| Currently Married | 44.3% | 33.1% | 48.0% |
| Married but Separated | 1.4% | 0.5% | 1.8% |
| Single Population | 54.3% | 66.4% | 50.2% |
| Never Married | 29.5% | 34.8% | 33.8% |
| Divorced | 17.1% | 21.3% | 10.8% |
| Widowed | 7.7% | 10.4% | 5.6% |
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| Household Size | 2.09 | 2.19 | 2.60 |
| Households | 2,845 | 1,844 | 124,010,992 |
| Family Households | 1,514 | 946 | 80,755,759 |
| Married couple, w/children | 19.5% | 22.1% | 30.5% |
| Married couple, no children | 49.2% | 34.0% | 42.9% |
| Non Family Households | 1,331 | 898 | 43,255,233 |
| Single householder, w/children | 20.6% | 23.3% | 15.8% |
| Single householder, no children | 10.7% | 20.6% | 10.8% |