| | Gallup, NM | Capitan, NM | United States |
| Population | 21,901 | 1,354 | 329,725,481 |
| Female Population | 50.2% | 48.2% | 50.5% |
| Male Population | 49.8% | 51.8% | 49.5% |
| Median Age | 34.5 | 41.5 | 38.4 |
| space3 | | | |
| Population - 2010 | 21,795 | 1,489 | 309,327,143 |
| Population - 2000 | 20,209 | 1,443 | 285,036,114 |
| Population - 1990 | 19,154 | 842 | 251,960,433 |
| Pop. 2000 to Now | 5.2% | 1.0% | 15.6% |
| Pop. 1990 to Now | 11.0% | 73.0% | 30.8% |
| space4 | | | |
| Population Density | 1,095.6 | 415.5 | 93.4 |
| Land Area | 20.0 | 3.3 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Gallup, NM | Capitan, NM | United States |
| Age 0 to 4 | 7.6% | 6.1% | 5.9% |
| Age 5 to 9 | 8.0% | 3.1% | 6.1% |
| Age 10 to 14 | 9.8% | 9.6% | 6.6% |
| Age 15 to 17 | 5.6% | 3.5% | 3.9% |
| Age 18 to 20 | 2.8% | 8.6% | 4.0% |
| Age 21 to 24 | 2.9% | 0.0% | 5.2% |
| Age 25 to 34 | 14.7% | 9.4% | 13.8% |
| Age 35 to 44 | 14.3% | 13.4% | 12.9% |
| Age 45 to 54 | 10.0% | 7.9% | 12.6% |
| Age 55 to 59 | 5.1% | 5.2% | 6.7% |
| Age 60 to 64 | 5.2% | 7.7% | 6.3% |
| Age 65 to 74 | 9.2% | 15.6% | 9.6% |
| Age 75 to 84 | 3.5% | 6.9% | 4.5% |
| Age 85 and over | 1.3% | 3.0% | 1.9% |
| space1 | | | |
| Race | | | |
| | Gallup, NM | Capitan, NM | United States |
| White | 16.8% | 50.5% | 59.4% |
| Black | 1.4% | 0.0% | 12.2% |
| Asian | 3.4% | 0.0% | 5.6% |
| Native American | 44.4% | 1.8% | 0.6% |
| Hawaiian, Pacific Islander | 0.2% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 2.0% | 1.6% | 3.2% |
| Hispanic | 31.7% | 46.0% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Gallup, NM | Capitan, NM | United States |
| Married Population | 40.7% | 42.9% | 49.8% |
| Currently Married | 37.7% | 42.9% | 48.0% |
| Married but Separated | 3.1% | 0.0% | 1.8% |
| Single Population | 59.3% | 57.1% | 50.2% |
| Never Married | 42.5% | 26.0% | 33.8% |
| Divorced | 12.0% | 15.7% | 10.8% |
| Widowed | 4.7% | 15.4% | 5.6% |
| space5 | | | |
| Household Size | 2.92 | 2.41 | 2.60 |
| Households | 7,313 | 561 | 124,010,992 |
| Family Households | 4,896 | 304 | 80,755,759 |
| Married couple, w/children | 24.8% | 21.4% | 30.5% |
| Married couple, no children | 31.1% | 52.0% | 42.9% |
| Non Family Households | 2,417 | 257 | 43,255,233 |
| Single householder, w/children | 29.4% | 15.5% | 15.8% |
| Single householder, no children | 14.6% | 11.2% | 10.8% |