| | Southgate, MI | Salem, MA | United States |
| Population | 29,990 | 44,452 | 329,725,481 |
| Female Population | 52.0% | 55.1% | 50.5% |
| Male Population | 48.1% | 44.9% | 49.5% |
| Median Age | 42.1 | 37.6 | 38.4 |
| space3 | | | |
| Population - 2010 | 29,977 | 41,823 | 309,327,143 |
| Population - 2000 | 30,136 | 40,407 | 285,036,114 |
| Population - 1990 | 30,771 | 38,091 | 251,960,433 |
| Pop. 2000 to Now | -3.3% | 7.9% | 15.6% |
| Pop. 1990 to Now | -5.3% | 14.4% | 30.8% |
| space4 | | | |
| Population Density | 4,362.2 | 5,359.5 | 93.4 |
| Land Area | 6.9 | 8.3 | 3,531,905.4 |
| Water Area | 0.0 | 10.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Southgate, MI | Salem, MA | United States |
| Age 0 to 4 | 5.5% | 5.1% | 5.9% |
| Age 5 to 9 | 5.2% | 4.1% | 6.1% |
| Age 10 to 14 | 5.6% | 4.2% | 6.6% |
| Age 15 to 17 | 2.5% | 2.0% | 3.9% |
| Age 18 to 20 | 2.2% | 4.5% | 4.0% |
| Age 21 to 24 | 5.5% | 7.8% | 5.2% |
| Age 25 to 34 | 16.2% | 18.2% | 13.8% |
| Age 35 to 44 | 11.4% | 13.5% | 12.9% |
| Age 45 to 54 | 12.8% | 11.6% | 12.6% |
| Age 55 to 59 | 6.9% | 6.8% | 6.7% |
| Age 60 to 64 | 8.0% | 6.0% | 6.3% |
| Age 65 to 74 | 10.9% | 9.6% | 9.6% |
| Age 75 to 84 | 4.9% | 4.2% | 4.5% |
| Age 85 and over | 2.4% | 2.3% | 1.9% |
| space1 | | | |
| Race | | | |
| | Southgate, MI | Salem, MA | United States |
| White | 78.7% | 72.0% | 59.4% |
| Black | 6.2% | 3.8% | 12.2% |
| Asian | 2.3% | 3.0% | 5.6% |
| Native American | 0.0% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.4% | 0.4% |
| Two or More Races | 2.4% | 2.9% | 3.2% |
| Hispanic | 10.4% | 17.7% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Southgate, MI | Salem, MA | United States |
| Married Population | 45.1% | 41.5% | 49.8% |
| Currently Married | 43.9% | 39.5% | 48.0% |
| Married but Separated | 1.1% | 2.0% | 1.8% |
| Single Population | 54.9% | 58.5% | 50.2% |
| Never Married | 34.3% | 43.5% | 33.8% |
| Divorced | 13.2% | 10.6% | 10.8% |
| Widowed | 7.5% | 4.4% | 5.6% |
| space5 | | | |
| Household Size | 2.38 | 2.17 | 2.60 |
| Households | 12,566 | 19,745 | 124,010,992 |
| Family Households | 7,562 | 10,225 | 80,755,759 |
| Married couple, w/children | 24.3% | 22.9% | 30.5% |
| Married couple, no children | 44.4% | 44.9% | 42.9% |
| Non Family Households | 5,004 | 9,520 | 43,255,233 |
| Single householder, w/children | 18.1% | 18.2% | 15.8% |
| Single householder, no children | 13.2% | 14.0% | 10.8% |