| | Warren, MN | Lake Mills, IA | United States |
| Population | 1,606 | 2,101 | 329,725,481 |
| Female Population | 50.8% | 53.4% | 50.5% |
| Male Population | 49.3% | 46.6% | 49.5% |
| Median Age | 36.7 | 41.2 | 38.4 |
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| Population - 2010 | 1,566 | 2,106 | 309,327,143 |
| Population - 2000 | 1,678 | 2,140 | 285,036,114 |
| Population - 1990 | 1,813 | 2,143 | 251,960,433 |
| Pop. 2000 to Now | -7.9% | -7.2% | 15.6% |
| Pop. 1990 to Now | -14.7% | -7.3% | 30.8% |
| space4 | | | |
| Population Density | 1,105.3 | 779.0 | 93.4 |
| Land Area | 1.5 | 2.7 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Warren, MN | Lake Mills, IA | United States |
| Age 0 to 4 | 7.5% | 2.9% | 5.9% |
| Age 5 to 9 | 5.9% | 6.4% | 6.1% |
| Age 10 to 14 | 6.0% | 6.3% | 6.6% |
| Age 15 to 17 | 5.0% | 5.1% | 3.9% |
| Age 18 to 20 | 2.6% | 3.8% | 4.0% |
| Age 21 to 24 | 4.9% | 4.9% | 5.2% |
| Age 25 to 34 | 15.9% | 12.5% | 13.8% |
| Age 35 to 44 | 9.9% | 11.3% | 12.9% |
| Age 45 to 54 | 6.3% | 9.6% | 12.6% |
| Age 55 to 59 | 11.0% | 9.7% | 6.7% |
| Age 60 to 64 | 6.1% | 3.7% | 6.3% |
| Age 65 to 74 | 8.2% | 7.1% | 9.6% |
| Age 75 to 84 | 6.3% | 11.4% | 4.5% |
| Age 85 and over | 4.6% | 5.3% | 1.9% |
| space1 | | | |
| Race | | | |
| | Warren, MN | Lake Mills, IA | United States |
| White | 89.5% | 90.2% | 59.4% |
| Black | 0.4% | 0.4% | 12.2% |
| Asian | 0.4% | 0.3% | 5.6% |
| Native American | 0.4% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.2% | 0.0% | 0.4% |
| Two or More Races | 2.1% | 0.6% | 3.2% |
| Hispanic | 6.8% | 8.5% | 18.4% |
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| Marriage & Family | | | |
| | Warren, MN | Lake Mills, IA | United States |
| Married Population | 44.4% | 44.5% | 49.8% |
| Currently Married | 44.0% | 43.6% | 48.0% |
| Married but Separated | 0.4% | 0.8% | 1.8% |
| Single Population | 55.6% | 55.5% | 50.2% |
| Never Married | 38.6% | 31.6% | 33.8% |
| Divorced | 9.1% | 12.6% | 10.8% |
| Widowed | 7.9% | 11.3% | 5.6% |
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| Household Size | 2.26 | 2.31 | 2.60 |
| Households | 688 | 894 | 124,010,992 |
| Family Households | 350 | 528 | 80,755,759 |
| Married couple, w/children | 21.4% | 24.4% | 30.5% |
| Married couple, no children | 50.6% | 48.3% | 42.9% |
| Non Family Households | 338 | 366 | 43,255,233 |
| Single householder, w/children | 23.4% | 14.8% | 15.8% |
| Single householder, no children | 4.6% | 12.5% | 10.8% |