| | League City, TX | Mansfield, TX | United States |
| Population | 111,847 | 71,375 | 329,725,481 |
| Female Population | 50.1% | 51.3% | 50.5% |
| Male Population | 49.9% | 48.8% | 49.5% |
| Median Age | 36.6 | 37.5 | 38.4 |
| space3 | | | |
| Population - 2010 | 84,099 | 57,091 | 309,327,143 |
| Population - 2000 | 45,444 | 28,031 | 285,036,114 |
| Population - 1990 | 30,159 | 15,607 | 251,960,433 |
| Pop. 2000 to Now | 138.7% | 160.8% | 15.6% |
| Pop. 1990 to Now | 259.7% | 368.3% | 30.8% |
| space4 | | | |
| Population Density | 2,181.9 | 1,948.2 | 93.4 |
| Land Area | 51.3 | 36.6 | 3,531,905.4 |
| Water Area | 1.7 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | League City, TX | Mansfield, TX | United States |
| Age 0 to 4 | 6.3% | 5.4% | 5.9% |
| Age 5 to 9 | 8.6% | 7.0% | 6.1% |
| Age 10 to 14 | 7.6% | 10.7% | 6.6% |
| Age 15 to 17 | 4.9% | 5.7% | 3.9% |
| Age 18 to 20 | 3.4% | 4.1% | 4.0% |
| Age 21 to 24 | 3.1% | 4.1% | 5.2% |
| Age 25 to 34 | 13.6% | 10.3% | 13.8% |
| Age 35 to 44 | 15.8% | 14.8% | 12.9% |
| Age 45 to 54 | 14.8% | 14.9% | 12.6% |
| Age 55 to 59 | 6.2% | 7.0% | 6.7% |
| Age 60 to 64 | 4.8% | 4.7% | 6.3% |
| Age 65 to 74 | 6.5% | 6.4% | 9.6% |
| Age 75 to 84 | 3.1% | 3.9% | 4.5% |
| Age 85 and over | 1.4% | 1.2% | 1.9% |
| space1 | | | |
| Race | | | |
| | League City, TX | Mansfield, TX | United States |
| White | 65.9% | 52.7% | 59.4% |
| Black | 7.8% | 22.2% | 12.2% |
| Asian | 6.3% | 3.7% | 5.6% |
| Native American | 0.1% | 0.2% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.2% | 0.4% | 0.4% |
| Two or More Races | 2.9% | 3.7% | 3.2% |
| Hispanic | 16.9% | 17.2% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | League City, TX | Mansfield, TX | United States |
| Married Population | 62.0% | 59.5% | 49.8% |
| Currently Married | 61.0% | 58.3% | 48.0% |
| Married but Separated | 0.9% | 1.2% | 1.8% |
| Single Population | 38.0% | 40.5% | 50.2% |
| Never Married | 25.9% | 28.9% | 33.8% |
| Divorced | 8.8% | 8.1% | 10.8% |
| Widowed | 3.3% | 3.6% | 5.6% |
| space5 | | | |
| Household Size | 2.72 | 3.07 | 2.60 |
| Households | 40,964 | 23,135 | 124,010,992 |
| Family Households | 30,031 | 18,484 | 80,755,759 |
| Married couple, w/children | 45.5% | 43.2% | 30.5% |
| Married couple, no children | 39.0% | 37.2% | 42.9% |
| Non Family Households | 10,933 | 4,651 | 43,255,233 |
| Single householder, w/children | 8.6% | 14.1% | 15.8% |
| Single householder, no children | 6.9% | 5.5% | 10.8% |