| | Alamo, TX | Weslaco, TX | United States |
| Population | 19,644 | 40,393 | 329,725,481 |
| Female Population | 50.8% | 51.3% | 50.5% |
| Male Population | 49.2% | 48.7% | 49.5% |
| Median Age | 30.1 | 29.4 | 38.4 |
| space3 | | | |
| Population - 2010 | 18,455 | 37,037 | 309,327,143 |
| Population - 2000 | 14,760 | 26,935 | 285,036,114 |
| Population - 1990 | 8,210 | 21,877 | 251,960,433 |
| Pop. 2000 to Now | 39.3% | 60.7% | 15.6% |
| Pop. 1990 to Now | 150.4% | 97.8% | 30.8% |
| space4 | | | |
| Population Density | 2,615.4 | 2,296.5 | 93.4 |
| Land Area | 7.5 | 17.6 | 3,531,905.4 |
| Water Area | 0.0 | 0.1 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Alamo, TX | Weslaco, TX | United States |
| Age 0 to 4 | 8.3% | 8.9% | 5.9% |
| Age 5 to 9 | 11.3% | 9.5% | 6.1% |
| Age 10 to 14 | 8.6% | 9.8% | 6.6% |
| Age 15 to 17 | 4.5% | 6.1% | 3.9% |
| Age 18 to 20 | 3.9% | 3.9% | 4.0% |
| Age 21 to 24 | 6.7% | 5.8% | 5.2% |
| Age 25 to 34 | 12.6% | 13.5% | 13.8% |
| Age 35 to 44 | 8.8% | 11.2% | 12.9% |
| Age 45 to 54 | 10.4% | 11.0% | 12.6% |
| Age 55 to 59 | 4.4% | 4.4% | 6.7% |
| Age 60 to 64 | 5.8% | 3.7% | 6.3% |
| Age 65 to 74 | 7.5% | 6.6% | 9.6% |
| Age 75 to 84 | 5.8% | 4.1% | 4.5% |
| Age 85 and over | 1.4% | 1.5% | 1.9% |
| space1 | | | |
| Race | | | |
| | Alamo, TX | Weslaco, TX | United States |
| White | 14.2% | 9.6% | 59.4% |
| Black | 0.0% | 1.2% | 12.2% |
| Asian | 0.0% | 0.4% | 5.6% |
| Native American | 0.0% | 0.2% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.1% | 0.4% |
| Two or More Races | 0.1% | 0.0% | 3.2% |
| Hispanic | 85.7% | 88.4% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Alamo, TX | Weslaco, TX | United States |
| Married Population | 55.7% | 51.1% | 49.8% |
| Currently Married | 52.6% | 48.3% | 48.0% |
| Married but Separated | 3.1% | 2.8% | 1.8% |
| Single Population | 44.3% | 48.9% | 50.2% |
| Never Married | 30.2% | 33.7% | 33.8% |
| Divorced | 6.6% | 9.3% | 10.8% |
| Widowed | 7.5% | 6.0% | 5.6% |
| space5 | | | |
| Household Size | 3.34 | 3.28 | 2.60 |
| Households | 5,884 | 12,198 | 124,010,992 |
| Family Households | 4,631 | 9,753 | 80,755,759 |
| Married couple, w/children | 33.2% | 37.3% | 30.5% |
| Married couple, no children | 33.7% | 25.5% | 42.9% |
| Non Family Households | 1,253 | 2,445 | 43,255,233 |
| Single householder, w/children | 22.7% | 22.1% | 15.8% |
| Single householder, no children | 10.5% | 15.0% | 10.8% |