| | Milton, WA | Idaho City, ID | United States |
| Population | 8,501 | 720 | 329,725,481 |
| Female Population | 50.4% | 53.2% | 50.5% |
| Male Population | 49.7% | 46.8% | 49.5% |
| Median Age | 37.3 | 38.8 | 38.4 |
| space3 | | | |
| Population - 2010 | 7,263 | 445 | 309,327,143 |
| Population - 2000 | 5,795 | 458 | 285,036,114 |
| Population - 1990 | 4,995 | 322 | 251,960,433 |
| Pop. 2000 to Now | 41.9% | 4.8% | 15.6% |
| Pop. 1990 to Now | 64.6% | 49.1% | 30.8% |
| space4 | | | |
| Population Density | 3,172.0 | 1,082.7 | 93.4 |
| Land Area | 2.7 | 0.7 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Milton, WA | Idaho City, ID | United States |
| Age 0 to 4 | 6.2% | 9.0% | 5.9% |
| Age 5 to 9 | 6.3% | 9.0% | 6.1% |
| Age 10 to 14 | 6.3% | 1.7% | 6.6% |
| Age 15 to 17 | 2.8% | 2.8% | 3.9% |
| Age 18 to 20 | 2.8% | 1.3% | 4.0% |
| Age 21 to 24 | 3.6% | 0.3% | 5.2% |
| Age 25 to 34 | 18.5% | 12.5% | 13.8% |
| Age 35 to 44 | 15.1% | 18.9% | 12.9% |
| Age 45 to 54 | 11.1% | 14.3% | 12.6% |
| Age 55 to 59 | 5.4% | 6.8% | 6.7% |
| Age 60 to 64 | 7.1% | 1.5% | 6.3% |
| Age 65 to 74 | 7.6% | 7.9% | 9.6% |
| Age 75 to 84 | 3.7% | 2.4% | 4.5% |
| Age 85 and over | 3.6% | 11.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Milton, WA | Idaho City, ID | United States |
| White | 71.8% | 88.5% | 59.4% |
| Black | 1.3% | 0.3% | 12.2% |
| Asian | 7.7% | 0.0% | 5.6% |
| Native American | 0.2% | 1.0% | 0.6% |
| Hawaiian, Pacific Islander | 1.2% | 0.0% | 0.2% |
| Other | 0.0% | 1.8% | 0.4% |
| Two or More Races | 6.7% | 0.0% | 3.2% |
| Hispanic | 11.2% | 8.5% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Milton, WA | Idaho City, ID | United States |
| Married Population | 46.3% | 64.5% | 49.8% |
| Currently Married | 45.8% | 63.1% | 48.0% |
| Married but Separated | 0.6% | 1.4% | 1.8% |
| Single Population | 53.7% | 35.5% | 50.2% |
| Never Married | 32.6% | 16.3% | 33.8% |
| Divorced | 14.4% | 13.3% | 10.8% |
| Widowed | 6.6% | 5.9% | 5.6% |
| space5 | | | |
| Household Size | 2.58 | 2.09 | 2.60 |
| Households | 3,288 | 342 | 124,010,992 |
| Family Households | 2,071 | 247 | 80,755,759 |
| Married couple, w/children | 25.1% | 44.1% | 30.5% |
| Married couple, no children | 42.7% | 40.5% | 42.9% |
| Non Family Households | 1,217 | 95 | 43,255,233 |
| Single householder, w/children | 19.3% | 14.6% | 15.8% |
| Single householder, no children | 12.9% | 0.8% | 10.8% |