| | Grand Junction, CO | San Marcos, CA | United States |
| Population | 65,067 | 94,313 | 329,725,481 |
| Female Population | 50.3% | 50.1% | 50.5% |
| Male Population | 49.7% | 49.9% | 49.5% |
| Median Age | 39.4 | 35.6 | 38.4 |
| space3 | | | |
| Population - 2010 | 58,842 | 83,948 | 309,327,143 |
| Population - 2000 | 41,986 | 54,977 | 285,036,114 |
| Population - 1990 | 29,034 | 38,974 | 251,960,433 |
| Pop. 2000 to Now | 51.1% | 77.3% | 15.6% |
| Pop. 1990 to Now | 118.5% | 150.1% | 30.8% |
| space4 | | | |
| Population Density | 1,652.8 | 3,872.3 | 93.4 |
| Land Area | 39.4 | 24.4 | 3,531,905.4 |
| Water Area | 0.5 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Grand Junction, CO | San Marcos, CA | United States |
| Age 0 to 4 | 5.5% | 6.9% | 5.9% |
| Age 5 to 9 | 5.5% | 8.0% | 6.1% |
| Age 10 to 14 | 5.2% | 8.0% | 6.6% |
| Age 15 to 17 | 2.5% | 3.5% | 3.9% |
| Age 18 to 20 | 5.6% | 5.2% | 4.0% |
| Age 21 to 24 | 6.0% | 4.5% | 5.2% |
| Age 25 to 34 | 14.3% | 12.9% | 13.8% |
| Age 35 to 44 | 12.6% | 15.9% | 12.9% |
| Age 45 to 54 | 10.8% | 12.4% | 12.6% |
| Age 55 to 59 | 5.6% | 5.5% | 6.7% |
| Age 60 to 64 | 7.4% | 4.6% | 6.3% |
| Age 65 to 74 | 10.7% | 7.5% | 9.6% |
| Age 75 to 84 | 5.3% | 3.3% | 4.5% |
| Age 85 and over | 3.2% | 1.8% | 1.9% |
| space1 | | | |
| Race | | | |
| | Grand Junction, CO | San Marcos, CA | United States |
| White | 79.0% | 43.5% | 59.4% |
| Black | 0.8% | 1.5% | 12.2% |
| Asian | 1.5% | 10.5% | 5.6% |
| Native American | 0.4% | 0.3% | 0.6% |
| Hawaiian, Pacific Islander | 0.2% | 0.0% | 0.2% |
| Other | 0.4% | 0.2% | 0.4% |
| Two or More Races | 2.0% | 4.2% | 3.2% |
| Hispanic | 15.7% | 39.7% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Grand Junction, CO | San Marcos, CA | United States |
| Married Population | 45.6% | 54.1% | 49.8% |
| Currently Married | 43.8% | 52.7% | 48.0% |
| Married but Separated | 1.8% | 1.4% | 1.8% |
| Single Population | 54.4% | 45.9% | 50.2% |
| Never Married | 32.8% | 31.5% | 33.8% |
| Divorced | 14.8% | 9.1% | 10.8% |
| Widowed | 6.8% | 5.2% | 5.6% |
| space5 | | | |
| Household Size | 2.27 | 3.08 | 2.60 |
| Households | 27,551 | 30,304 | 124,010,992 |
| Family Households | 14,817 | 22,517 | 80,755,759 |
| Married couple, w/children | 29.8% | 40.9% | 30.5% |
| Married couple, no children | 46.3% | 35.3% | 42.9% |
| Non Family Households | 12,734 | 7,787 | 43,255,233 |
| Single householder, w/children | 14.5% | 14.4% | 15.8% |
| Single householder, no children | 9.4% | 9.4% | 10.8% |