| | Merrill, WI | Big Flats, WI | United States |
| Population | 9,344 | 925 | 329,725,481 |
| Female Population | 53.1% | 41.3% | 50.5% |
| Male Population | 47.0% | 58.7% | 49.5% |
| Median Age | 44.1 | 54.5 | 38.4 |
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| Population - 2010 | 9,648 | 1,019 | 309,327,143 |
| Population - 2000 | 10,146 | 946 | 285,036,114 |
| Population - 1990 | 9,860 | 731 | 251,960,433 |
| Pop. 2000 to Now | -11.4% | 7.1% | 15.6% |
| Pop. 1990 to Now | -8.8% | 38.6% | 30.8% |
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| Population Density | 1,268.2 | 19.3 | 93.4 |
| Land Area | 7.4 | 47.9 | 3,531,905.4 |
| Water Area | 0.6 | 0.2 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Merrill, WI | Big Flats, WI | United States |
| Age 0 to 4 | 5.7% | 3.8% | 5.9% |
| Age 5 to 9 | 4.0% | 4.4% | 6.1% |
| Age 10 to 14 | 4.3% | 5.0% | 6.6% |
| Age 15 to 17 | 3.4% | 2.5% | 3.9% |
| Age 18 to 20 | 2.2% | 0.4% | 4.0% |
| Age 21 to 24 | 6.2% | 5.4% | 5.2% |
| Age 25 to 34 | 12.6% | 11.7% | 13.8% |
| Age 35 to 44 | 12.6% | 6.3% | 12.9% |
| Age 45 to 54 | 15.0% | 12.4% | 12.6% |
| Age 55 to 59 | 6.8% | 5.6% | 6.7% |
| Age 60 to 64 | 6.7% | 9.2% | 6.3% |
| Age 65 to 74 | 9.3% | 18.5% | 9.6% |
| Age 75 to 84 | 7.0% | 8.9% | 4.5% |
| Age 85 and over | 4.1% | 5.9% | 1.9% |
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| Race | | | |
| | Merrill, WI | Big Flats, WI | United States |
| White | 95.4% | 96.2% | 59.4% |
| Black | 0.7% | 0.0% | 12.2% |
| Asian | 0.5% | 0.3% | 5.6% |
| Native American | 0.3% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 1.9% | 2.8% | 3.2% |
| Hispanic | 1.2% | 0.6% | 18.4% |
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| Marriage & Family | | | |
| | Merrill, WI | Big Flats, WI | United States |
| Married Population | 43.3% | 44.8% | 49.8% |
| Currently Married | 42.4% | 44.8% | 48.0% |
| Married but Separated | 0.9% | 0.0% | 1.8% |
| Single Population | 56.7% | 55.2% | 50.2% |
| Never Married | 31.4% | 21.9% | 33.8% |
| Divorced | 16.6% | 20.4% | 10.8% |
| Widowed | 8.6% | 12.8% | 5.6% |
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| Household Size | 2.17 | 2.11 | 2.60 |
| Households | 4,165 | 438 | 124,010,992 |
| Family Households | 2,172 | 215 | 80,755,759 |
| Married couple, w/children | 23.1% | 29.8% | 30.5% |
| Married couple, no children | 50.6% | 54.0% | 42.9% |
| Non Family Households | 1,993 | 223 | 43,255,233 |
| Single householder, w/children | 19.6% | 11.6% | 15.8% |
| Single householder, no children | 6.8% | 4.7% | 10.8% |