| | Upper Montclair, NJ | Boulder, CO | United States |
| Population | 12,033 | 104,930 | 329,725,481 |
| Female Population | 50.5% | 48.5% | 50.5% |
| Male Population | 49.5% | 51.5% | 49.5% |
| Median Age | 42.3 | 28.9 | 38.4 |
| space3 | | | |
| Population - 2010 | 11,599 | 97,724 | 309,327,143 |
| Population - 2000 | 11,594 | 94,673 | 285,036,114 |
| Population - 1990 | 11,923 | 83,312 | 251,960,433 |
| Pop. 2000 to Now | 2.2% | 13.7% | 15.6% |
| Pop. 1990 to Now | -0.7% | 29.2% | 30.8% |
| space4 | | | |
| Population Density | 4,828.7 | 3,991.4 | 93.4 |
| Land Area | 2.5 | 26.3 | 3,531,905.4 |
| Water Area | 0.0 | 1.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Upper Montclair, NJ | Boulder, CO | United States |
| Age 0 to 4 | 6.8% | 2.7% | 5.9% |
| Age 5 to 9 | 9.6% | 3.7% | 6.1% |
| Age 10 to 14 | 8.5% | 3.6% | 6.6% |
| Age 15 to 17 | 5.4% | 2.5% | 3.9% |
| Age 18 to 20 | 2.9% | 16.2% | 4.0% |
| Age 21 to 24 | 2.3% | 13.8% | 5.2% |
| Age 25 to 34 | 4.4% | 16.3% | 13.8% |
| Age 35 to 44 | 13.8% | 10.3% | 12.9% |
| Age 45 to 54 | 17.8% | 10.3% | 12.6% |
| Age 55 to 59 | 6.5% | 4.5% | 6.7% |
| Age 60 to 64 | 8.2% | 4.2% | 6.3% |
| Age 65 to 74 | 9.7% | 7.0% | 9.6% |
| Age 75 to 84 | 2.8% | 3.1% | 4.5% |
| Age 85 and over | 1.3% | 1.8% | 1.9% |
| space1 | | | |
| Race | | | |
| | Upper Montclair, NJ | Boulder, CO | United States |
| White | 79.0% | 78.3% | 59.4% |
| Black | 4.4% | 1.0% | 12.2% |
| Asian | 4.2% | 5.9% | 5.6% |
| Native American | 0.0% | 0.2% | 0.6% |
| Hawaiian, Pacific Islander | 0.2% | 0.0% | 0.2% |
| Other | 0.3% | 0.3% | 0.4% |
| Two or More Races | 4.9% | 3.5% | 3.2% |
| Hispanic | 6.9% | 10.6% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Upper Montclair, NJ | Boulder, CO | United States |
| Married Population | 67.4% | 31.9% | 49.8% |
| Currently Married | 66.8% | 31.2% | 48.0% |
| Married but Separated | 0.6% | 0.7% | 1.8% |
| Single Population | 32.6% | 68.1% | 50.2% |
| Never Married | 23.9% | 56.1% | 33.8% |
| Divorced | 5.5% | 9.5% | 10.8% |
| Widowed | 3.2% | 2.5% | 5.6% |
| space5 | | | |
| Household Size | 3.04 | 2.21 | 2.60 |
| Households | 3,950 | 42,610 | 124,010,992 |
| Family Households | 3,263 | 17,341 | 80,755,759 |
| Married couple, w/children | 50.3% | 33.3% | 30.5% |
| Married couple, no children | 41.1% | 47.4% | 42.9% |
| Non Family Households | 687 | 25,269 | 43,255,233 |
| Single householder, w/children | 4.4% | 10.8% | 15.8% |
| Single householder, no children | 4.3% | 8.5% | 10.8% |