| | Boulder Junction, WI | Madison, WI | United States |
| Population | 1,400 | 265,447 | 329,725,481 |
| Female Population | 50.9% | 50.0% | 50.5% |
| Male Population | 49.1% | 50.0% | 49.5% |
| Median Age | 54.2 | 31.5 | 38.4 |
| space3 | | | |
| Population - 2010 | 939 | 233,977 | 309,327,143 |
| Population - 2000 | 958 | 208,054 | 285,036,114 |
| Population - 1990 | 884 | 191,262 | 251,960,433 |
| Pop. 2000 to Now | 1.4% | 26.5% | 15.6% |
| Pop. 1990 to Now | 9.8% | 37.6% | 30.8% |
| space4 | | | |
| Population Density | 18.1 | 3,368.1 | 93.4 |
| Land Area | 77.2 | 78.8 | 3,531,905.4 |
| Water Area | 20.8 | 22.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Boulder Junction, WI | Madison, WI | United States |
| Age 0 to 4 | 3.0% | 5.1% | 5.9% |
| Age 5 to 9 | 3.9% | 4.4% | 6.1% |
| Age 10 to 14 | 3.7% | 4.6% | 6.6% |
| Age 15 to 17 | 3.7% | 2.4% | 3.9% |
| Age 18 to 20 | 0.9% | 8.3% | 4.0% |
| Age 21 to 24 | 9.9% | 12.1% | 5.2% |
| Age 25 to 34 | 4.1% | 19.2% | 13.8% |
| Age 35 to 44 | 9.8% | 12.5% | 12.9% |
| Age 45 to 54 | 12.1% | 9.6% | 12.6% |
| Age 55 to 59 | 6.1% | 5.0% | 6.7% |
| Age 60 to 64 | 13.9% | 4.7% | 6.3% |
| Age 65 to 74 | 18.7% | 7.4% | 9.6% |
| Age 75 to 84 | 7.6% | 3.3% | 4.5% |
| Age 85 and over | 2.6% | 1.3% | 1.9% |
| space1 | | | |
| Race | | | |
| | Boulder Junction, WI | Madison, WI | United States |
| White | 94.2% | 72.0% | 59.4% |
| Black | 0.0% | 6.7% | 12.2% |
| Asian | 0.0% | 8.9% | 5.6% |
| Native American | 0.4% | 0.3% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.4% | 0.4% |
| Two or More Races | 1.5% | 4.0% | 3.2% |
| Hispanic | 3.9% | 7.8% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Boulder Junction, WI | Madison, WI | United States |
| Married Population | 62.6% | 38.0% | 49.8% |
| Currently Married | 62.3% | 37.2% | 48.0% |
| Married but Separated | 0.3% | 0.7% | 1.8% |
| Single Population | 37.4% | 62.0% | 50.2% |
| Never Married | 22.0% | 50.3% | 33.8% |
| Divorced | 10.1% | 8.5% | 10.8% |
| Widowed | 5.3% | 3.3% | 5.6% |
| space5 | | | |
| Household Size | 2.36 | 2.16 | 2.60 |
| Households | 592 | 117,324 | 124,010,992 |
| Family Households | 405 | 52,482 | 80,755,759 |
| Married couple, w/children | 15.1% | 31.3% | 30.5% |
| Married couple, no children | 74.3% | 46.1% | 42.9% |
| Non Family Households | 187 | 64,842 | 43,255,233 |
| Single householder, w/children | 8.1% | 14.7% | 15.8% |
| Single householder, no children | 2.5% | 7.9% | 10.8% |