| | Sweeny, TX | Lake Jackson, TX | United States |
| Population | 3,638 | 28,008 | 329,725,481 |
| Female Population | 50.0% | 49.4% | 50.5% |
| Male Population | 50.0% | 50.6% | 49.5% |
| Median Age | 32.5 | 33.8 | 38.4 |
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| Population - 2010 | 3,679 | 26,816 | 309,327,143 |
| Population - 2000 | 3,624 | 26,386 | 285,036,114 |
| Population - 1990 | 3,297 | 22,776 | 251,960,433 |
| Pop. 2000 to Now | -0.2% | 2.6% | 15.6% |
| Pop. 1990 to Now | 9.7% | 18.8% | 30.8% |
| space4 | | | |
| Population Density | 1,813.6 | 1,419.4 | 93.4 |
| Land Area | 2.0 | 19.7 | 3,531,905.4 |
| Water Area | 0.0 | 1.5 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Sweeny, TX | Lake Jackson, TX | United States |
| Age 0 to 4 | 6.7% | 6.4% | 5.9% |
| Age 5 to 9 | 10.4% | 8.1% | 6.1% |
| Age 10 to 14 | 10.5% | 7.5% | 6.6% |
| Age 15 to 17 | 4.5% | 3.9% | 3.9% |
| Age 18 to 20 | 3.7% | 3.6% | 4.0% |
| Age 21 to 24 | 3.3% | 5.6% | 5.2% |
| Age 25 to 34 | 16.3% | 16.5% | 13.8% |
| Age 35 to 44 | 6.4% | 11.9% | 12.9% |
| Age 45 to 54 | 9.1% | 10.7% | 12.6% |
| Age 55 to 59 | 8.2% | 7.9% | 6.7% |
| Age 60 to 64 | 5.7% | 5.3% | 6.3% |
| Age 65 to 74 | 6.8% | 7.8% | 9.6% |
| Age 75 to 84 | 2.5% | 3.2% | 4.5% |
| Age 85 and over | 6.0% | 1.6% | 1.9% |
| space1 | | | |
| Race | | | |
| | Sweeny, TX | Lake Jackson, TX | United States |
| White | 53.3% | 60.6% | 59.4% |
| Black | 12.8% | 4.7% | 12.2% |
| Asian | 0.2% | 2.6% | 5.6% |
| Native American | 0.0% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.7% | 0.4% |
| Two or More Races | 3.6% | 1.7% | 3.2% |
| Hispanic | 30.1% | 29.7% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Sweeny, TX | Lake Jackson, TX | United States |
| Married Population | 50.2% | 55.4% | 49.8% |
| Currently Married | 49.2% | 54.1% | 48.0% |
| Married but Separated | 1.1% | 1.3% | 1.8% |
| Single Population | 49.8% | 44.6% | 50.2% |
| Never Married | 27.4% | 31.3% | 33.8% |
| Divorced | 12.9% | 8.8% | 10.8% |
| Widowed | 9.5% | 4.5% | 5.6% |
| space5 | | | |
| Household Size | 2.66 | 2.69 | 2.60 |
| Households | 1,335 | 10,376 | 124,010,992 |
| Family Households | 929 | 7,050 | 80,755,759 |
| Married couple, w/children | 36.0% | 34.0% | 30.5% |
| Married couple, no children | 30.5% | 45.1% | 42.9% |
| Non Family Households | 406 | 3,326 | 43,255,233 |
| Single householder, w/children | 26.6% | 15.6% | 15.8% |
| Single householder, no children | 7.0% | 5.2% | 10.8% |