| | South Branch, MN | Lewisville, MN | United States |
| Population | 192 | 286 | 329,725,481 |
| Female Population | 50.0% | 52.5% | 50.5% |
| Male Population | 50.0% | 47.6% | 49.5% |
| Median Age | 55 | 45.5 | 38.4 |
| space3 | | | |
| Population - 2010 | 281 | 250 | 309,327,143 |
| Population - 2000 | 303 | 274 | 285,036,114 |
| Population - 1990 | 316 | 255 | 251,960,433 |
| Pop. 2000 to Now | -8.9% | -11.0% | 15.6% |
| Pop. 1990 to Now | -12.7% | -4.3% | 30.8% |
| space4 | | | |
| Population Density | 4.9 | 1,201.7 | 93.4 |
| Land Area | 39.1 | 0.2 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | South Branch, MN | Lewisville, MN | United States |
| Age 0 to 4 | 1.6% | 7.3% | 5.9% |
| Age 5 to 9 | 1.0% | 1.4% | 6.1% |
| Age 10 to 14 | 2.6% | 5.9% | 6.6% |
| Age 15 to 17 | 0.5% | 2.4% | 3.9% |
| Age 18 to 20 | 7.8% | 2.4% | 4.0% |
| Age 21 to 24 | 7.3% | 11.5% | 5.2% |
| Age 25 to 34 | 6.8% | 9.1% | 13.8% |
| Age 35 to 44 | 3.6% | 9.8% | 12.9% |
| Age 45 to 54 | 18.8% | 10.5% | 12.6% |
| Age 55 to 59 | 16.1% | 5.6% | 6.7% |
| Age 60 to 64 | 10.4% | 13.6% | 6.3% |
| Age 65 to 74 | 18.2% | 8.7% | 9.6% |
| Age 75 to 84 | 3.1% | 10.1% | 4.5% |
| Age 85 and over | 2.1% | 1.4% | 1.9% |
| space1 | | | |
| Race | | | |
| | South Branch, MN | Lewisville, MN | United States |
| White | 94.8% | 62.9% | 59.4% |
| Black | 0.0% | 0.0% | 12.2% |
| Asian | 0.0% | 3.1% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 5.2% | 0.0% | 3.2% |
| Hispanic | 0.0% | 33.9% | 18.4% |
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| Marriage & Family | | | |
| | South Branch, MN | Lewisville, MN | United States |
| Married Population | 71.4% | 35.2% | 49.8% |
| Currently Married | 71.4% | 35.2% | 48.0% |
| Married but Separated | 0.0% | 0.0% | 1.8% |
| Single Population | 28.6% | 64.8% | 50.2% |
| Never Married | 23.6% | 34.0% | 33.8% |
| Divorced | 3.8% | 18.9% | 10.8% |
| Widowed | 1.1% | 11.9% | 5.6% |
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| Household Size | 2.37 | 2.62 | 2.60 |
| Households | 81 | 109 | 124,010,992 |
| Family Households | 74 | 56 | 80,755,759 |
| Married couple, w/children | 8.1% | 14.3% | 30.5% |
| Married couple, no children | 79.7% | 46.4% | 42.9% |
| Non Family Households | 7 | 53 | 43,255,233 |
| Single householder, w/children | 6.8% | 26.8% | 15.8% |
| Single householder, no children | 5.4% | 12.5% | 10.8% |