| | Los Alamos, NM | Montrose, CO | United States |
| Population | 13,270 | 20,098 | 329,725,481 |
| Female Population | 48.6% | 53.6% | 50.5% |
| Male Population | 51.5% | 46.4% | 49.5% |
| Median Age | 41.4 | 48.3 | 38.4 |
| space3 | | | |
| Population - 2010 | 12,030 | 19,110 | 309,327,143 |
| Population - 2000 | 11,909 | 12,344 | 285,036,114 |
| Population - 1990 | 11,455 | 8,854 | 251,960,433 |
| Pop. 2000 to Now | 10.2% | 61.2% | 15.6% |
| Pop. 1990 to Now | 14.6% | 124.8% | 30.8% |
| space4 | | | |
| Population Density | 1,192.8 | 1,093.7 | 93.4 |
| Land Area | 11.1 | 18.4 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Los Alamos, NM | Montrose, CO | United States |
| Age 0 to 4 | 3.9% | 4.8% | 5.9% |
| Age 5 to 9 | 5.2% | 4.9% | 6.1% |
| Age 10 to 14 | 7.2% | 6.8% | 6.6% |
| Age 15 to 17 | 4.2% | 3.6% | 3.9% |
| Age 18 to 20 | 2.5% | 3.0% | 4.0% |
| Age 21 to 24 | 4.4% | 3.1% | 5.2% |
| Age 25 to 34 | 14.9% | 10.3% | 13.8% |
| Age 35 to 44 | 11.7% | 10.5% | 12.9% |
| Age 45 to 54 | 13.3% | 11.9% | 12.6% |
| Age 55 to 59 | 10.0% | 7.5% | 6.7% |
| Age 60 to 64 | 5.7% | 6.9% | 6.3% |
| Age 65 to 74 | 9.6% | 15.7% | 9.6% |
| Age 75 to 84 | 4.4% | 8.0% | 4.5% |
| Age 85 and over | 3.1% | 3.1% | 1.9% |
| space1 | | | |
| Race | | | |
| | Los Alamos, NM | Montrose, CO | United States |
| White | 67.6% | 76.1% | 59.4% |
| Black | 1.1% | 0.2% | 12.2% |
| Asian | 7.2% | 1.0% | 5.6% |
| Native American | 0.8% | 0.6% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.3% | 0.2% |
| Other | 0.0% | 0.1% | 0.4% |
| Two or More Races | 4.2% | 1.3% | 3.2% |
| Hispanic | 19.1% | 20.5% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Los Alamos, NM | Montrose, CO | United States |
| Married Population | 57.1% | 55.7% | 49.8% |
| Currently Married | 56.7% | 54.5% | 48.0% |
| Married but Separated | 0.4% | 1.2% | 1.8% |
| Single Population | 42.9% | 44.3% | 50.2% |
| Never Married | 27.2% | 23.4% | 33.8% |
| Divorced | 12.4% | 13.7% | 10.8% |
| Widowed | 3.2% | 7.2% | 5.6% |
| space5 | | | |
| Household Size | 2.24 | 2.35 | 2.60 |
| Households | 5,881 | 8,392 | 124,010,992 |
| Family Households | 3,546 | 5,332 | 80,755,759 |
| Married couple, w/children | 34.0% | 23.0% | 30.5% |
| Married couple, no children | 48.7% | 52.5% | 42.9% |
| Non Family Households | 2,335 | 3,060 | 43,255,233 |
| Single householder, w/children | 10.5% | 12.8% | 15.8% |
| Single householder, no children | 6.8% | 11.6% | 10.8% |