| | Willmar, MN | St. Cloud, MN | United States |
| Population | 20,823 | 68,430 | 329,725,481 |
| Female Population | 51.6% | 49.5% | 50.5% |
| Male Population | 48.4% | 50.5% | 49.5% |
| Median Age | 34.2 | 30.4 | 38.4 |
| space3 | | | |
| Population - 2010 | 19,580 | 66,099 | 309,327,143 |
| Population - 2000 | 18,351 | 59,107 | 285,036,114 |
| Population - 1990 | 17,531 | 48,812 | 251,960,433 |
| Pop. 2000 to Now | 8.4% | 15.9% | 15.6% |
| Pop. 1990 to Now | 13.5% | 40.4% | 30.8% |
| space4 | | | |
| Population Density | 1,490.4 | 1,710.4 | 93.4 |
| Land Area | 14.0 | 40.0 | 3,531,905.4 |
| Water Area | 1.3 | 1.1 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Willmar, MN | St. Cloud, MN | United States |
| Age 0 to 4 | 7.8% | 6.3% | 5.9% |
| Age 5 to 9 | 7.5% | 5.5% | 6.1% |
| Age 10 to 14 | 7.6% | 6.1% | 6.6% |
| Age 15 to 17 | 3.4% | 3.4% | 3.9% |
| Age 18 to 20 | 4.8% | 8.4% | 4.0% |
| Age 21 to 24 | 5.6% | 11.4% | 5.2% |
| Age 25 to 34 | 14.4% | 14.7% | 13.8% |
| Age 35 to 44 | 11.5% | 11.0% | 12.9% |
| Age 45 to 54 | 9.9% | 9.7% | 12.6% |
| Age 55 to 59 | 5.7% | 5.2% | 6.7% |
| Age 60 to 64 | 5.6% | 5.3% | 6.3% |
| Age 65 to 74 | 9.2% | 7.6% | 9.6% |
| Age 75 to 84 | 3.4% | 3.5% | 4.5% |
| Age 85 and over | 3.5% | 1.9% | 1.9% |
| space1 | | | |
| Race | | | |
| | Willmar, MN | St. Cloud, MN | United States |
| White | 61.6% | 70.7% | 59.4% |
| Black | 11.1% | 16.4% | 12.2% |
| Asian | 1.1% | 3.5% | 5.6% |
| Native American | 0.6% | 0.4% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.2% | 0.4% | 0.4% |
| Two or More Races | 2.1% | 4.6% | 3.2% |
| Hispanic | 23.4% | 4.1% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Willmar, MN | St. Cloud, MN | United States |
| Married Population | 47.4% | 38.6% | 49.8% |
| Currently Married | 46.5% | 37.8% | 48.0% |
| Married but Separated | 0.9% | 0.8% | 1.8% |
| Single Population | 52.6% | 61.4% | 50.2% |
| Never Married | 37.0% | 47.1% | 33.8% |
| Divorced | 9.3% | 10.0% | 10.8% |
| Widowed | 6.3% | 4.2% | 5.6% |
| space5 | | | |
| Household Size | 2.56 | 2.37 | 2.60 |
| Households | 7,775 | 27,028 | 124,010,992 |
| Family Households | 4,857 | 14,559 | 80,755,759 |
| Married couple, w/children | 27.9% | 29.1% | 30.5% |
| Married couple, no children | 43.0% | 38.6% | 42.9% |
| Non Family Households | 2,918 | 12,469 | 43,255,233 |
| Single householder, w/children | 20.2% | 21.9% | 15.8% |
| Single householder, no children | 9.0% | 10.4% | 10.8% |