| | Newtown, CT | Southbury, CT | United States |
| Population | 27,388 | 19,866 | 329,725,481 |
| Female Population | 49.5% | 52.8% | 50.5% |
| Male Population | 50.6% | 47.2% | 49.5% |
| Median Age | 45.4 | 50.8 | 38.4 |
| space3 | | | |
| Population - 2010 | 27,578 | 19,900 | 309,327,143 |
| Population - 2000 | 25,031 | 18,567 | 285,036,114 |
| Population - 1990 | 20,779 | 15,818 | 251,960,433 |
| Pop. 2000 to Now | 11.2% | 5.0% | 15.6% |
| Pop. 1990 to Now | 33.9% | 23.3% | 30.8% |
| space4 | | | |
| Population Density | 475.0 | 509.5 | 93.4 |
| Land Area | 57.7 | 39.0 | 3,531,905.4 |
| Water Area | 1.4 | 1.1 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Newtown, CT | Southbury, CT | United States |
| Age 0 to 4 | 4.1% | 4.0% | 5.9% |
| Age 5 to 9 | 6.3% | 4.2% | 6.1% |
| Age 10 to 14 | 5.9% | 7.0% | 6.6% |
| Age 15 to 17 | 5.5% | 4.1% | 3.9% |
| Age 18 to 20 | 3.8% | 2.6% | 4.0% |
| Age 21 to 24 | 4.9% | 3.5% | 5.2% |
| Age 25 to 34 | 7.9% | 7.5% | 13.8% |
| Age 35 to 44 | 10.7% | 10.3% | 12.9% |
| Age 45 to 54 | 16.5% | 13.8% | 12.6% |
| Age 55 to 59 | 9.6% | 7.3% | 6.7% |
| Age 60 to 64 | 7.9% | 7.1% | 6.3% |
| Age 65 to 74 | 9.6% | 13.7% | 9.6% |
| Age 75 to 84 | 5.0% | 9.3% | 4.5% |
| Age 85 and over | 2.2% | 5.5% | 1.9% |
| space1 | | | |
| Race | | | |
| | Newtown, CT | Southbury, CT | United States |
| White | 86.5% | 86.3% | 59.4% |
| Black | 1.7% | 2.1% | 12.2% |
| Asian | 2.2% | 3.2% | 5.6% |
| Native American | 0.1% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.2% | 0.0% | 0.2% |
| Other | 0.5% | 0.2% | 0.4% |
| Two or More Races | 2.0% | 1.7% | 3.2% |
| Hispanic | 6.9% | 6.4% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Newtown, CT | Southbury, CT | United States |
| Married Population | 56.2% | 57.0% | 49.8% |
| Currently Married | 55.6% | 56.6% | 48.0% |
| Married but Separated | 0.6% | 0.4% | 1.8% |
| Single Population | 43.8% | 43.0% | 50.2% |
| Never Married | 29.8% | 22.9% | 33.8% |
| Divorced | 8.4% | 11.9% | 10.8% |
| Widowed | 5.6% | 8.2% | 5.6% |
| space5 | | | |
| Household Size | 2.78 | 2.42 | 2.60 |
| Households | 9,655 | 8,029 | 124,010,992 |
| Family Households | 7,498 | 5,199 | 80,755,759 |
| Married couple, w/children | 34.5% | 33.0% | 30.5% |
| Married couple, no children | 48.6% | 54.3% | 42.9% |
| Non Family Households | 2,157 | 2,830 | 43,255,233 |
| Single householder, w/children | 9.1% | 4.4% | 15.8% |
| Single householder, no children | 7.8% | 8.2% | 10.8% |