| | South Hadley, MA | Elkton, MD | United States |
| Population | 18,051 | 15,724 | 329,725,481 |
| Female Population | 59.9% | 49.1% | 50.5% |
| Male Population | 40.1% | 50.9% | 49.5% |
| Median Age | 42.1 | 36 | 38.4 |
| space3 | | | |
| Population - 2010 | 17,737 | 15,474 | 309,327,143 |
| Population - 2000 | 17,196 | 11,893 | 285,036,114 |
| Population - 1990 | 16,685 | 9,073 | 251,960,433 |
| Pop. 2000 to Now | 2.0% | 31.7% | 15.6% |
| Pop. 1990 to Now | 5.1% | 72.7% | 30.8% |
| space4 | | | |
| Population Density | 1,019.1 | 1,769.3 | 93.4 |
| Land Area | 17.7 | 8.9 | 3,531,905.4 |
| Water Area | 0.7 | 0.3 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | South Hadley, MA | Elkton, MD | United States |
| Age 0 to 4 | 3.5% | 5.6% | 5.9% |
| Age 5 to 9 | 3.6% | 6.4% | 6.1% |
| Age 10 to 14 | 3.8% | 5.2% | 6.6% |
| Age 15 to 17 | 3.3% | 4.1% | 3.9% |
| Age 18 to 20 | 11.9% | 3.9% | 4.0% |
| Age 21 to 24 | 7.3% | 7.1% | 5.2% |
| Age 25 to 34 | 9.1% | 17.1% | 13.8% |
| Age 35 to 44 | 10.5% | 12.1% | 12.9% |
| Age 45 to 54 | 10.7% | 13.5% | 12.6% |
| Age 55 to 59 | 6.7% | 6.0% | 6.7% |
| Age 60 to 64 | 7.3% | 5.8% | 6.3% |
| Age 65 to 74 | 11.9% | 8.8% | 9.6% |
| Age 75 to 84 | 6.7% | 2.9% | 4.5% |
| Age 85 and over | 3.8% | 1.5% | 1.9% |
| space1 | | | |
| Race | | | |
| | South Hadley, MA | Elkton, MD | United States |
| White | 84.9% | 67.2% | 59.4% |
| Black | 1.5% | 14.9% | 12.2% |
| Asian | 5.2% | 2.6% | 5.6% |
| Native American | 0.1% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 2.3% | 7.5% | 3.2% |
| Hispanic | 5.9% | 7.8% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | South Hadley, MA | Elkton, MD | United States |
| Married Population | 43.3% | 43.8% | 49.8% |
| Currently Married | 42.2% | 42.0% | 48.0% |
| Married but Separated | 1.2% | 1.8% | 1.8% |
| Single Population | 56.7% | 56.2% | 50.2% |
| Never Married | 38.6% | 38.2% | 33.8% |
| Divorced | 12.0% | 11.6% | 10.8% |
| Widowed | 6.1% | 6.5% | 5.6% |
| space5 | | | |
| Household Size | 2.13 | 2.57 | 2.60 |
| Households | 7,328 | 5,849 | 124,010,992 |
| Family Households | 4,408 | 3,851 | 80,755,759 |
| Married couple, w/children | 21.5% | 22.4% | 30.5% |
| Married couple, no children | 55.4% | 36.1% | 42.9% |
| Non Family Households | 2,920 | 1,998 | 43,255,233 |
| Single householder, w/children | 10.4% | 24.0% | 15.8% |
| Single householder, no children | 12.7% | 17.5% | 10.8% |