| | Severn, MD | Clarksburg, MD | United States |
| Population | 53,955 | 27,354 | 329,725,481 |
| Female Population | 50.7% | 51.6% | 50.5% |
| Male Population | 49.3% | 48.4% | 49.5% |
| Median Age | 35.8 | 36.4 | 38.4 |
| space3 | | | |
| Population - 2010 | 41,753 | 10,543 | 309,327,143 |
| Population - 2000 | 35,076 | 1,834 | 285,036,114 |
| Population - 1990 | 24,499 | 2,426 | 251,960,433 |
| Pop. 2000 to Now | 44.8% | 1,126.5% | 15.6% |
| Pop. 1990 to Now | 107.3% | 827.2% | 30.8% |
| space4 | | | |
| Population Density | 2,945.3 | 3,330.2 | 93.4 |
| Land Area | 18.3 | 8.2 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Severn, MD | Clarksburg, MD | United States |
| Age 0 to 4 | 6.7% | 9.0% | 5.9% |
| Age 5 to 9 | 7.3% | 8.8% | 6.1% |
| Age 10 to 14 | 6.8% | 10.5% | 6.6% |
| Age 15 to 17 | 2.7% | 4.4% | 3.9% |
| Age 18 to 20 | 2.4% | 2.2% | 4.0% |
| Age 21 to 24 | 5.1% | 1.9% | 5.2% |
| Age 25 to 34 | 17.3% | 10.7% | 13.8% |
| Age 35 to 44 | 14.9% | 18.6% | 12.9% |
| Age 45 to 54 | 12.8% | 16.2% | 12.6% |
| Age 55 to 59 | 6.9% | 5.1% | 6.7% |
| Age 60 to 64 | 5.2% | 4.7% | 6.3% |
| Age 65 to 74 | 8.7% | 5.8% | 9.6% |
| Age 75 to 84 | 2.6% | 2.0% | 4.5% |
| Age 85 and over | 0.5% | 0.3% | 1.9% |
| space1 | | | |
| Race | | | |
| | Severn, MD | Clarksburg, MD | United States |
| White | 46.8% | 27.3% | 59.4% |
| Black | 30.8% | 15.6% | 12.2% |
| Asian | 8.8% | 40.0% | 5.6% |
| Native American | 0.0% | 0.4% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.3% | 1.3% | 0.4% |
| Two or More Races | 5.8% | 4.3% | 3.2% |
| Hispanic | 7.6% | 11.0% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Severn, MD | Clarksburg, MD | United States |
| Married Population | 56.0% | 68.3% | 49.8% |
| Currently Married | 54.8% | 67.0% | 48.0% |
| Married but Separated | 1.2% | 1.3% | 1.8% |
| Single Population | 44.0% | 31.7% | 50.2% |
| Never Married | 30.4% | 19.9% | 33.8% |
| Divorced | 9.7% | 7.6% | 10.8% |
| Widowed | 3.9% | 4.2% | 5.6% |
| space5 | | | |
| Household Size | 2.67 | 3.28 | 2.60 |
| Households | 20,187 | 8,329 | 124,010,992 |
| Family Households | 14,679 | 7,125 | 80,755,759 |
| Married couple, w/children | 32.9% | 53.9% | 30.5% |
| Married couple, no children | 43.3% | 27.9% | 42.9% |
| Non Family Households | 5,508 | 1,204 | 43,255,233 |
| Single householder, w/children | 13.0% | 11.2% | 15.8% |
| Single householder, no children | 10.7% | 6.9% | 10.8% |