| | Weslaco, TX | Waco, TX | United States |
| Population | 40,393 | 136,800 | 329,725,481 |
| Female Population | 51.3% | 51.7% | 50.5% |
| Male Population | 48.7% | 48.3% | 49.5% |
| Median Age | 29.4 | 29.1 | 38.4 |
| space3 | | | |
| Population - 2010 | 37,037 | 125,360 | 309,327,143 |
| Population - 2000 | 26,935 | 113,726 | 285,036,114 |
| Population - 1990 | 21,877 | 103,590 | 251,960,433 |
| Pop. 2000 to Now | 60.7% | 24.3% | 15.6% |
| Pop. 1990 to Now | 97.8% | 36.5% | 30.8% |
| space4 | | | |
| Population Density | 2,296.5 | 1,536.7 | 93.4 |
| Land Area | 17.6 | 89.0 | 3,531,905.4 |
| Water Area | 0.1 | 12.3 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Weslaco, TX | Waco, TX | United States |
| Age 0 to 4 | 8.9% | 7.5% | 5.9% |
| Age 5 to 9 | 9.5% | 5.9% | 6.1% |
| Age 10 to 14 | 9.8% | 6.6% | 6.6% |
| Age 15 to 17 | 6.1% | 3.8% | 3.9% |
| Age 18 to 20 | 3.9% | 9.1% | 4.0% |
| Age 21 to 24 | 5.8% | 10.6% | 5.2% |
| Age 25 to 34 | 13.5% | 13.9% | 13.8% |
| Age 35 to 44 | 11.2% | 11.1% | 12.9% |
| Age 45 to 54 | 11.0% | 9.3% | 12.6% |
| Age 55 to 59 | 4.4% | 5.1% | 6.7% |
| Age 60 to 64 | 3.7% | 4.6% | 6.3% |
| Age 65 to 74 | 6.6% | 7.3% | 9.6% |
| Age 75 to 84 | 4.1% | 3.4% | 4.5% |
| Age 85 and over | 1.5% | 1.9% | 1.9% |
| space1 | | | |
| Race | | | |
| | Weslaco, TX | Waco, TX | United States |
| White | 9.6% | 44.1% | 59.4% |
| Black | 1.2% | 20.5% | 12.2% |
| Asian | 0.4% | 2.1% | 5.6% |
| Native American | 0.2% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.1% | 0.2% | 0.4% |
| Two or More Races | 0.0% | 2.0% | 3.2% |
| Hispanic | 88.4% | 31.0% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Weslaco, TX | Waco, TX | United States |
| Married Population | 51.1% | 38.1% | 49.8% |
| Currently Married | 48.3% | 36.1% | 48.0% |
| Married but Separated | 2.8% | 2.0% | 1.8% |
| Single Population | 48.9% | 61.9% | 50.2% |
| Never Married | 33.7% | 45.4% | 33.8% |
| Divorced | 9.3% | 11.1% | 10.8% |
| Widowed | 6.0% | 5.4% | 5.6% |
| space5 | | | |
| Household Size | 3.28 | 2.52 | 2.60 |
| Households | 12,198 | 50,990 | 124,010,992 |
| Family Households | 9,753 | 29,026 | 80,755,759 |
| Married couple, w/children | 37.3% | 28.2% | 30.5% |
| Married couple, no children | 25.5% | 33.3% | 42.9% |
| Non Family Households | 2,445 | 21,964 | 43,255,233 |
| Single householder, w/children | 22.1% | 26.2% | 15.8% |
| Single householder, no children | 15.0% | 12.4% | 10.8% |