| | Marathon, TX | Fort Stockton, TX | United States |
| Population | 427 | 8,433 | 329,725,481 |
| Female Population | 59.5% | 48.2% | 50.5% |
| Male Population | 40.5% | 51.8% | 49.5% |
| Median Age | 56.1 | 35.4 | 38.4 |
| space3 | | | |
| Population - 2010 | 456 | 8,354 | 309,327,143 |
| Population - 2000 | 455 | 7,846 | 285,036,114 |
| Population - 1990 | 507 | 8,524 | 251,960,433 |
| Pop. 2000 to Now | 9.5% | 6.7% | 15.6% |
| Pop. 1990 to Now | -1.8% | -1.8% | 30.8% |
| space4 | | | |
| Population Density | 81.2 | 1,578.0 | 93.4 |
| Land Area | 5.3 | 5.3 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Marathon, TX | Fort Stockton, TX | United States |
| Age 0 to 4 | 4.7% | 6.8% | 5.9% |
| Age 5 to 9 | 0.0% | 8.0% | 6.1% |
| Age 10 to 14 | 3.7% | 8.1% | 6.6% |
| Age 15 to 17 | 3.5% | 3.3% | 3.9% |
| Age 18 to 20 | 0.0% | 4.3% | 4.0% |
| Age 21 to 24 | 0.9% | 4.6% | 5.2% |
| Age 25 to 34 | 17.1% | 14.6% | 13.8% |
| Age 35 to 44 | 6.3% | 13.5% | 12.9% |
| Age 45 to 54 | 8.2% | 11.0% | 12.6% |
| Age 55 to 59 | 14.1% | 5.9% | 6.7% |
| Age 60 to 64 | 16.6% | 3.9% | 6.3% |
| Age 65 to 74 | 9.8% | 9.0% | 9.6% |
| Age 75 to 84 | 13.1% | 5.3% | 4.5% |
| Age 85 and over | 1.9% | 1.6% | 1.9% |
| space1 | | | |
| Race | | | |
| | Marathon, TX | Fort Stockton, TX | United States |
| White | 55.0% | 18.7% | 59.4% |
| Black | 0.0% | 2.1% | 12.2% |
| Asian | 0.0% | 0.1% | 5.6% |
| Native American | 0.0% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.2% | 0.2% |
| Other | 0.0% | 0.3% | 0.4% |
| Two or More Races | 0.0% | 1.4% | 3.2% |
| Hispanic | 45.0% | 77.2% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Marathon, TX | Fort Stockton, TX | United States |
| Married Population | 65.0% | 45.6% | 49.8% |
| Currently Married | 63.9% | 43.8% | 48.0% |
| Married but Separated | 1.0% | 1.8% | 1.8% |
| Single Population | 35.0% | 54.4% | 50.2% |
| Never Married | 12.0% | 32.0% | 33.8% |
| Divorced | 17.4% | 14.9% | 10.8% |
| Widowed | 5.6% | 7.5% | 5.6% |
| space5 | | | |
| Household Size | 1.53 | 2.41 | 2.60 |
| Households | 279 | 3,224 | 124,010,992 |
| Family Households | 210 | 2,067 | 80,755,759 |
| Married couple, w/children | 11.0% | 28.0% | 30.5% |
| Married couple, no children | 30.0% | 34.9% | 42.9% |
| Non Family Households | 69 | 1,157 | 43,255,233 |
| Single householder, w/children | 39.0% | 24.3% | 15.8% |
| Single householder, no children | 20.0% | 12.8% | 10.8% |