| | Idalou, TX | Alpine, TX | United States |
| Population | 2,068 | 5,884 | 329,725,481 |
| Female Population | 49.8% | 52.7% | 50.5% |
| Male Population | 50.2% | 47.3% | 49.5% |
| Median Age | 39.1 | 43.2 | 38.4 |
| space3 | | | |
| Population - 2010 | 2,305 | 6,025 | 309,327,143 |
| Population - 2000 | 2,157 | 5,786 | 285,036,114 |
| Population - 1990 | 2,074 | 5,637 | 251,960,433 |
| Pop. 2000 to Now | 7.2% | 4.3% | 15.6% |
| Pop. 1990 to Now | 11.5% | 7.1% | 30.8% |
| space4 | | | |
| Population Density | 2,047.5 | 1,225.3 | 93.4 |
| Land Area | 1.0 | 4.8 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Idalou, TX | Alpine, TX | United States |
| Age 0 to 4 | 3.2% | 5.4% | 5.9% |
| Age 5 to 9 | 5.6% | 5.8% | 6.1% |
| Age 10 to 14 | 13.1% | 3.6% | 6.6% |
| Age 15 to 17 | 3.7% | 3.8% | 3.9% |
| Age 18 to 20 | 2.4% | 2.2% | 4.0% |
| Age 21 to 24 | 4.7% | 5.3% | 5.2% |
| Age 25 to 34 | 11.9% | 14.1% | 13.8% |
| Age 35 to 44 | 7.7% | 12.7% | 12.9% |
| Age 45 to 54 | 12.3% | 15.3% | 12.6% |
| Age 55 to 59 | 12.8% | 4.8% | 6.7% |
| Age 60 to 64 | 4.3% | 6.9% | 6.3% |
| Age 65 to 74 | 8.8% | 13.9% | 9.6% |
| Age 75 to 84 | 7.5% | 4.4% | 4.5% |
| Age 85 and over | 2.0% | 1.8% | 1.9% |
| space1 | | | |
| Race | | | |
| | Idalou, TX | Alpine, TX | United States |
| White | 42.7% | 41.5% | 59.4% |
| Black | 0.7% | 0.4% | 12.2% |
| Asian | 0.0% | 5.5% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 0.9% | 0.6% | 3.2% |
| Hispanic | 55.8% | 52.1% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Idalou, TX | Alpine, TX | United States |
| Married Population | 56.3% | 48.2% | 49.8% |
| Currently Married | 55.9% | 46.4% | 48.0% |
| Married but Separated | 0.4% | 1.8% | 1.8% |
| Single Population | 43.8% | 51.8% | 50.2% |
| Never Married | 27.6% | 29.6% | 33.8% |
| Divorced | 9.6% | 13.2% | 10.8% |
| Widowed | 6.6% | 9.0% | 5.6% |
| space5 | | | |
| Household Size | 2.39 | 1.95 | 2.60 |
| Households | 860 | 2,980 | 124,010,992 |
| Family Households | 568 | 1,373 | 80,755,759 |
| Married couple, w/children | 32.4% | 33.9% | 30.5% |
| Married couple, no children | 43.1% | 44.8% | 42.9% |
| Non Family Households | 292 | 1,607 | 43,255,233 |
| Single householder, w/children | 15.8% | 10.1% | 15.8% |
| Single householder, no children | 8.6% | 11.1% | 10.8% |