| | Smyrna, TN | Mount Juliet, TN | United States |
| Population | 52,401 | 38,059 | 329,725,481 |
| Female Population | 50.6% | 49.6% | 50.5% |
| Male Population | 49.4% | 50.4% | 49.5% |
| Median Age | 34.4 | 38.4 | 38.4 |
| space3 | | | |
| Population - 2010 | 40,589 | 24,988 | 309,327,143 |
| Population - 2000 | 25,569 | 12,366 | 285,036,114 |
| Population - 1990 | 13,647 | 5,389 | 251,960,433 |
| Pop. 2000 to Now | 108.0% | 211.6% | 15.6% |
| Pop. 1990 to Now | 289.7% | 614.9% | 30.8% |
| space4 | | | |
| Population Density | 1,729.0 | 1,534.5 | 93.4 |
| Land Area | 30.3 | 24.8 | 3,531,905.4 |
| Water Area | 0.1 | 0.3 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Smyrna, TN | Mount Juliet, TN | United States |
| Age 0 to 4 | 7.6% | 6.4% | 5.9% |
| Age 5 to 9 | 7.3% | 8.3% | 6.1% |
| Age 10 to 14 | 6.8% | 7.8% | 6.6% |
| Age 15 to 17 | 3.5% | 4.5% | 3.9% |
| Age 18 to 20 | 4.2% | 2.6% | 4.0% |
| Age 21 to 24 | 5.3% | 4.3% | 5.2% |
| Age 25 to 34 | 16.3% | 10.7% | 13.8% |
| Age 35 to 44 | 14.9% | 16.2% | 12.9% |
| Age 45 to 54 | 13.0% | 13.2% | 12.6% |
| Age 55 to 59 | 6.4% | 5.8% | 6.7% |
| Age 60 to 64 | 5.1% | 6.1% | 6.3% |
| Age 65 to 74 | 5.9% | 9.5% | 9.6% |
| Age 75 to 84 | 3.0% | 3.7% | 4.5% |
| Age 85 and over | 0.7% | 0.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Smyrna, TN | Mount Juliet, TN | United States |
| White | 61.6% | 79.0% | 59.4% |
| Black | 17.0% | 7.0% | 12.2% |
| Asian | 5.0% | 3.9% | 5.6% |
| Native American | 0.2% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.1% | 0.1% | 0.2% |
| Other | 0.3% | 1.8% | 0.4% |
| Two or More Races | 3.6% | 2.1% | 3.2% |
| Hispanic | 12.3% | 6.0% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Smyrna, TN | Mount Juliet, TN | United States |
| Married Population | 48.3% | 60.9% | 49.8% |
| Currently Married | 47.2% | 60.3% | 48.0% |
| Married but Separated | 1.1% | 0.6% | 1.8% |
| Single Population | 51.7% | 39.1% | 50.2% |
| Never Married | 34.2% | 23.3% | 33.8% |
| Divorced | 11.6% | 11.3% | 10.8% |
| Widowed | 5.9% | 4.5% | 5.6% |
| space5 | | | |
| Household Size | 2.74 | 2.78 | 2.60 |
| Households | 19,022 | 13,672 | 124,010,992 |
| Family Households | 13,173 | 10,446 | 80,755,759 |
| Married couple, w/children | 31.5% | 40.2% | 30.5% |
| Married couple, no children | 36.2% | 41.9% | 42.9% |
| Non Family Households | 5,849 | 3,226 | 43,255,233 |
| Single householder, w/children | 20.4% | 13.9% | 15.8% |
| Single householder, no children | 12.0% | 4.0% | 10.8% |