| | North Bethesda, MD | Southborough, MA | United States |
| Population | 50,695 | 10,380 | 329,725,481 |
| Female Population | 51.3% | 53.1% | 50.5% |
| Male Population | 48.7% | 46.9% | 49.5% |
| Median Age | 39.6 | 42.5 | 38.4 |
| space3 | | | |
| Population - 2010 | 40,489 | 9,775 | 309,327,143 |
| Population - 2000 | 38,610 | 8,781 | 285,036,114 |
| Population - 1990 | 29,656 | 6,628 | 251,960,433 |
| Pop. 2000 to Now | 32.0% | 16.2% | 15.6% |
| Pop. 1990 to Now | 71.8% | 53.9% | 30.8% |
| space4 | | | |
| Population Density | 5,717.3 | 740.3 | 93.4 |
| Land Area | 8.9 | 14.0 | 3,531,905.4 |
| Water Area | 0.0 | 1.5 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | North Bethesda, MD | Southborough, MA | United States |
| Age 0 to 4 | 4.6% | 6.5% | 5.9% |
| Age 5 to 9 | 5.0% | 6.8% | 6.1% |
| Age 10 to 14 | 6.5% | 8.9% | 6.6% |
| Age 15 to 17 | 3.1% | 5.1% | 3.9% |
| Age 18 to 20 | 1.9% | 2.4% | 4.0% |
| Age 21 to 24 | 4.7% | 3.5% | 5.2% |
| Age 25 to 34 | 17.1% | 8.7% | 13.8% |
| Age 35 to 44 | 14.4% | 12.8% | 12.9% |
| Age 45 to 54 | 13.9% | 18.8% | 12.6% |
| Age 55 to 59 | 6.9% | 7.0% | 6.7% |
| Age 60 to 64 | 5.9% | 6.1% | 6.3% |
| Age 65 to 74 | 7.9% | 7.5% | 9.6% |
| Age 75 to 84 | 5.3% | 4.5% | 4.5% |
| Age 85 and over | 2.6% | 1.5% | 1.9% |
| space1 | | | |
| Race | | | |
| | North Bethesda, MD | Southborough, MA | United States |
| White | 51.2% | 78.3% | 59.4% |
| Black | 11.1% | 0.5% | 12.2% |
| Asian | 15.3% | 16.4% | 5.6% |
| Native American | 0.1% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.8% | 1.6% | 0.4% |
| Two or More Races | 5.5% | 0.8% | 3.2% |
| Hispanic | 16.0% | 2.5% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | North Bethesda, MD | Southborough, MA | United States |
| Married Population | 50.7% | 64.6% | 49.8% |
| Currently Married | 48.9% | 64.4% | 48.0% |
| Married but Separated | 1.8% | 0.2% | 1.8% |
| Single Population | 49.3% | 35.4% | 50.2% |
| Never Married | 33.5% | 24.1% | 33.8% |
| Divorced | 10.1% | 5.4% | 10.8% |
| Widowed | 5.7% | 5.9% | 5.6% |
| space5 | | | |
| Household Size | 2.27 | 2.86 | 2.60 |
| Households | 21,901 | 3,579 | 124,010,992 |
| Family Households | 11,697 | 2,776 | 80,755,759 |
| Married couple, w/children | 35.6% | 52.3% | 30.5% |
| Married couple, no children | 45.1% | 38.5% | 42.9% |
| Non Family Households | 10,204 | 803 | 43,255,233 |
| Single householder, w/children | 12.7% | 4.9% | 15.8% |
| Single householder, no children | 6.6% | 4.4% | 10.8% |