| | Terrell, TX | Forney, TX | United States |
| Population | 17,083 | 22,770 | 329,725,481 |
| Female Population | 55.0% | 47.4% | 50.5% |
| Male Population | 45.0% | 52.6% | 49.5% |
| Median Age | 34.4 | 32.3 | 38.4 |
| space3 | | | |
| Population - 2010 | 16,123 | 13,946 | 309,327,143 |
| Population - 2000 | 13,606 | 5,588 | 285,036,114 |
| Population - 1990 | 12,490 | 4,070 | 251,960,433 |
| Pop. 2000 to Now | 44.7% | 423.4% | 15.6% |
| Pop. 1990 to Now | 57.7% | 618.6% | 30.8% |
| space4 | | | |
| Population Density | 751.2 | 1,538.8 | 93.4 |
| Land Area | 22.7 | 14.8 | 3,531,905.4 |
| Water Area | 0.3 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Terrell, TX | Forney, TX | United States |
| Age 0 to 4 | 6.8% | 9.2% | 5.9% |
| Age 5 to 9 | 6.7% | 7.7% | 6.1% |
| Age 10 to 14 | 8.2% | 6.2% | 6.6% |
| Age 15 to 17 | 6.0% | 4.9% | 3.9% |
| Age 18 to 20 | 4.2% | 4.7% | 4.0% |
| Age 21 to 24 | 4.1% | 5.7% | 5.2% |
| Age 25 to 34 | 14.9% | 17.0% | 13.8% |
| Age 35 to 44 | 10.6% | 15.3% | 12.9% |
| Age 45 to 54 | 12.3% | 12.2% | 12.6% |
| Age 55 to 59 | 5.7% | 5.0% | 6.7% |
| Age 60 to 64 | 5.6% | 4.1% | 6.3% |
| Age 65 to 74 | 7.9% | 5.4% | 9.6% |
| Age 75 to 84 | 4.9% | 2.0% | 4.5% |
| Age 85 and over | 2.2% | 0.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Terrell, TX | Forney, TX | United States |
| White | 40.7% | 62.2% | 59.4% |
| Black | 23.1% | 15.6% | 12.2% |
| Asian | 0.1% | 2.0% | 5.6% |
| Native American | 0.6% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.1% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 2.3% | 1.8% | 3.2% |
| Hispanic | 33.1% | 18.4% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Terrell, TX | Forney, TX | United States |
| Married Population | 47.4% | 56.1% | 49.8% |
| Currently Married | 43.5% | 56.0% | 48.0% |
| Married but Separated | 3.9% | 0.1% | 1.8% |
| Single Population | 52.6% | 43.9% | 50.2% |
| Never Married | 30.0% | 28.6% | 33.8% |
| Divorced | 16.0% | 12.2% | 10.8% |
| Widowed | 6.6% | 3.1% | 5.6% |
| space5 | | | |
| Household Size | 2.76 | 2.90 | 2.60 |
| Households | 5,991 | 7,860 | 124,010,992 |
| Family Households | 4,235 | 5,931 | 80,755,759 |
| Married couple, w/children | 33.4% | 46.3% | 30.5% |
| Married couple, no children | 26.1% | 31.3% | 42.9% |
| Non Family Households | 1,756 | 1,929 | 43,255,233 |
| Single householder, w/children | 28.0% | 17.7% | 15.8% |
| Single householder, no children | 12.5% | 4.7% | 10.8% |