| | Upper Marlboro, MD | Waldorf, MD | United States |
| Population | 621 | 79,190 | 329,725,481 |
| Female Population | 54.8% | 53.1% | 50.5% |
| Male Population | 45.3% | 46.9% | 49.5% |
| Median Age | 38.5 | 36.3 | 38.4 |
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| Population - 2010 | 686 | 67,143 | 309,327,143 |
| Population - 2000 | 648 | 22,312 | 285,036,114 |
| Population - 1990 | 745 | 15,058 | 251,960,433 |
| Pop. 2000 to Now | 3.7% | 246.4% | 15.6% |
| Pop. 1990 to Now | -9.8% | 413.3% | 30.8% |
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| Population Density | 1,511.0 | 2,184.0 | 93.4 |
| Land Area | 0.4 | 36.3 | 3,531,905.4 |
| Water Area | 0.0 | 0.2 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Upper Marlboro, MD | Waldorf, MD | United States |
| Age 0 to 4 | 4.0% | 5.9% | 5.9% |
| Age 5 to 9 | 4.2% | 7.8% | 6.1% |
| Age 10 to 14 | 6.6% | 7.0% | 6.6% |
| Age 15 to 17 | 4.0% | 4.2% | 3.9% |
| Age 18 to 20 | 2.1% | 3.3% | 4.0% |
| Age 21 to 24 | 2.1% | 5.1% | 5.2% |
| Age 25 to 34 | 18.4% | 14.9% | 13.8% |
| Age 35 to 44 | 23.0% | 14.7% | 12.9% |
| Age 45 to 54 | 11.6% | 14.4% | 12.6% |
| Age 55 to 59 | 9.0% | 6.1% | 6.7% |
| Age 60 to 64 | 6.0% | 6.1% | 6.3% |
| Age 65 to 74 | 6.8% | 7.0% | 9.6% |
| Age 75 to 84 | 1.6% | 2.5% | 4.5% |
| Age 85 and over | 0.6% | 1.0% | 1.9% |
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| Race | | | |
| | Upper Marlboro, MD | Waldorf, MD | United States |
| White | 36.4% | 21.1% | 59.4% |
| Black | 62.0% | 61.0% | 12.2% |
| Asian | 0.0% | 3.5% | 5.6% |
| Native American | 0.0% | 0.4% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.6% | 0.4% |
| Two or More Races | 1.6% | 5.2% | 3.2% |
| Hispanic | 0.0% | 8.2% | 18.4% |
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| Marriage & Family | | | |
| | Upper Marlboro, MD | Waldorf, MD | United States |
| Married Population | 23.4% | 46.6% | 49.8% |
| Currently Married | 20.8% | 44.6% | 48.0% |
| Married but Separated | 2.6% | 1.9% | 1.8% |
| Single Population | 76.6% | 53.4% | 50.2% |
| Never Married | 56.0% | 38.6% | 33.8% |
| Divorced | 17.4% | 11.0% | 10.8% |
| Widowed | 3.2% | 3.9% | 5.6% |
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| Household Size | 2.06 | 2.74 | 2.60 |
| Households | 302 | 28,852 | 124,010,992 |
| Family Households | 135 | 20,507 | 80,755,759 |
| Married couple, w/children | 8.9% | 30.6% | 30.5% |
| Married couple, no children | 29.6% | 33.4% | 42.9% |
| Non Family Households | 167 | 8,345 | 43,255,233 |
| Single householder, w/children | 38.5% | 22.8% | 15.8% |
| Single householder, no children | 23.0% | 13.3% | 10.8% |