| | Willits, CA | Hamilton, MT | United States |
| Population | 5,008 | 4,632 | 329,725,481 |
| Female Population | 54.1% | 56.1% | 50.5% |
| Male Population | 45.9% | 43.9% | 49.5% |
| Median Age | 41.7 | 48.5 | 38.4 |
| space3 | | | |
| Population - 2010 | 4,922 | 4,288 | 309,327,143 |
| Population - 2000 | 5,073 | 3,705 | 285,036,114 |
| Population - 1990 | 5,027 | 2,737 | 251,960,433 |
| Pop. 2000 to Now | -4.8% | 36.5% | 15.6% |
| Pop. 1990 to Now | -3.9% | 84.7% | 30.8% |
| space4 | | | |
| Population Density | 1,777.8 | 1,910.9 | 93.4 |
| Land Area | 2.8 | 2.4 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Willits, CA | Hamilton, MT | United States |
| Age 0 to 4 | 4.5% | 6.7% | 5.9% |
| Age 5 to 9 | 5.6% | 2.4% | 6.1% |
| Age 10 to 14 | 7.4% | 2.2% | 6.6% |
| Age 15 to 17 | 1.7% | 2.3% | 3.9% |
| Age 18 to 20 | 3.4% | 1.6% | 4.0% |
| Age 21 to 24 | 5.0% | 4.9% | 5.2% |
| Age 25 to 34 | 12.8% | 10.0% | 13.8% |
| Age 35 to 44 | 12.7% | 16.0% | 12.9% |
| Age 45 to 54 | 9.2% | 11.1% | 12.6% |
| Age 55 to 59 | 3.8% | 5.9% | 6.7% |
| Age 60 to 64 | 3.8% | 6.6% | 6.3% |
| Age 65 to 74 | 16.7% | 14.1% | 9.6% |
| Age 75 to 84 | 9.5% | 8.8% | 4.5% |
| Age 85 and over | 4.1% | 7.6% | 1.9% |
| space1 | | | |
| Race | | | |
| | Willits, CA | Hamilton, MT | United States |
| White | 68.7% | 91.3% | 59.4% |
| Black | 1.0% | 0.0% | 12.2% |
| Asian | 0.2% | 0.8% | 5.6% |
| Native American | 1.5% | 1.8% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 4.1% | 2.1% | 3.2% |
| Hispanic | 24.5% | 4.0% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Willits, CA | Hamilton, MT | United States |
| Married Population | 32.1% | 40.5% | 49.8% |
| Currently Married | 29.1% | 39.7% | 48.0% |
| Married but Separated | 3.1% | 0.8% | 1.8% |
| Single Population | 67.9% | 59.5% | 50.2% |
| Never Married | 33.7% | 23.6% | 33.8% |
| Divorced | 22.2% | 21.3% | 10.8% |
| Widowed | 12.0% | 14.6% | 5.6% |
| space5 | | | |
| Household Size | 2.13 | 1.68 | 2.60 |
| Households | 2,311 | 2,652 | 124,010,992 |
| Family Households | 982 | 1,155 | 80,755,759 |
| Married couple, w/children | 22.4% | 22.2% | 30.5% |
| Married couple, no children | 29.6% | 48.4% | 42.9% |
| Non Family Households | 1,329 | 1,497 | 43,255,233 |
| Single householder, w/children | 28.3% | 15.5% | 15.8% |
| Single householder, no children | 19.7% | 13.9% | 10.8% |