| | Sykesville, MD | Selbyville, DE | United States |
| Population | 4,260 | 2,806 | 329,725,481 |
| Female Population | 49.1% | 46.3% | 50.5% |
| Male Population | 50.9% | 53.7% | 49.5% |
| Median Age | 32.9 | 43.5 | 38.4 |
| space3 | | | |
| Population - 2010 | 3,943 | 2,165 | 309,327,143 |
| Population - 2000 | 4,197 | 1,645 | 285,036,114 |
| Population - 1990 | 2,303 | 1,335 | 251,960,433 |
| Pop. 2000 to Now | -5.3% | 59.1% | 15.6% |
| Pop. 1990 to Now | 72.5% | 96.0% | 30.8% |
| space4 | | | |
| Population Density | 2,703.1 | 778.6 | 93.4 |
| Land Area | 1.6 | 3.6 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Sykesville, MD | Selbyville, DE | United States |
| Age 0 to 4 | 8.7% | 2.9% | 5.9% |
| Age 5 to 9 | 7.2% | 8.7% | 6.1% |
| Age 10 to 14 | 8.5% | 4.6% | 6.6% |
| Age 15 to 17 | 6.5% | 1.0% | 3.9% |
| Age 18 to 20 | 6.0% | 2.1% | 4.0% |
| Age 21 to 24 | 3.9% | 5.2% | 5.2% |
| Age 25 to 34 | 13.1% | 15.0% | 13.8% |
| Age 35 to 44 | 14.1% | 12.0% | 12.9% |
| Age 45 to 54 | 15.7% | 14.9% | 12.6% |
| Age 55 to 59 | 3.3% | 6.5% | 6.7% |
| Age 60 to 64 | 3.9% | 4.6% | 6.3% |
| Age 65 to 74 | 5.3% | 14.4% | 9.6% |
| Age 75 to 84 | 2.3% | 7.6% | 4.5% |
| Age 85 and over | 1.5% | 0.5% | 1.9% |
| space1 | | | |
| Race | | | |
| | Sykesville, MD | Selbyville, DE | United States |
| White | 78.5% | 74.8% | 59.4% |
| Black | 11.0% | 6.5% | 12.2% |
| Asian | 3.9% | 0.4% | 5.6% |
| Native American | 0.4% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 2.7% | 1.7% | 3.2% |
| Hispanic | 3.6% | 16.6% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Sykesville, MD | Selbyville, DE | United States |
| Married Population | 55.7% | 57.6% | 49.8% |
| Currently Married | 51.8% | 52.9% | 48.0% |
| Married but Separated | 3.9% | 4.7% | 1.8% |
| Single Population | 44.3% | 42.4% | 50.2% |
| Never Married | 31.8% | 27.4% | 33.8% |
| Divorced | 8.4% | 9.7% | 10.8% |
| Widowed | 4.1% | 5.2% | 5.6% |
| space5 | | | |
| Household Size | 2.91 | 2.99 | 2.60 |
| Households | 1,429 | 937 | 124,010,992 |
| Family Households | 1,019 | 719 | 80,755,759 |
| Married couple, w/children | 54.2% | 25.3% | 30.5% |
| Married couple, no children | 24.1% | 53.4% | 42.9% |
| Non Family Households | 410 | 218 | 43,255,233 |
| Single householder, w/children | 15.3% | 9.9% | 15.8% |
| Single householder, no children | 6.4% | 11.4% | 10.8% |