| | Jefferson, MD | Littlestown, PA | United States |
| Population | 2,556 | 4,730 | 329,725,481 |
| Female Population | 52.1% | 50.8% | 50.5% |
| Male Population | 47.9% | 49.2% | 49.5% |
| Median Age | 38.8 | 36.6 | 38.4 |
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| Population - 2010 | 1,869 | 4,436 | 309,327,143 |
| Population - 2000 | 2,089 | 3,947 | 285,036,114 |
| Population - 1990 | 995 | 2,974 | 251,960,433 |
| Pop. 2000 to Now | 14.1% | 14.0% | 15.6% |
| Pop. 1990 to Now | 139.5% | 51.2% | 30.8% |
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| Population Density | 1,218.3 | 3,147.0 | 93.4 |
| Land Area | 2.1 | 1.5 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Jefferson, MD | Littlestown, PA | United States |
| Age 0 to 4 | 7.3% | 6.2% | 5.9% |
| Age 5 to 9 | 8.1% | 9.2% | 6.1% |
| Age 10 to 14 | 6.8% | 5.5% | 6.6% |
| Age 15 to 17 | 2.5% | 5.8% | 3.9% |
| Age 18 to 20 | 3.8% | 4.9% | 4.0% |
| Age 21 to 24 | 4.3% | 2.2% | 5.2% |
| Age 25 to 34 | 13.1% | 14.1% | 13.8% |
| Age 35 to 44 | 10.8% | 10.9% | 12.9% |
| Age 45 to 54 | 13.7% | 12.0% | 12.6% |
| Age 55 to 59 | 8.1% | 7.7% | 6.7% |
| Age 60 to 64 | 8.5% | 6.9% | 6.3% |
| Age 65 to 74 | 7.6% | 9.4% | 9.6% |
| Age 75 to 84 | 4.0% | 4.3% | 4.5% |
| Age 85 and over | 1.4% | 0.9% | 1.9% |
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| Race | | | |
| | Jefferson, MD | Littlestown, PA | United States |
| White | 86.0% | 92.0% | 59.4% |
| Black | 2.7% | 1.4% | 12.2% |
| Asian | 3.3% | 0.3% | 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 | 2.0% | 1.6% | 3.2% |
| Hispanic | 5.8% | 4.7% | 18.4% |
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| Marriage & Family | | | |
| | Jefferson, MD | Littlestown, PA | United States |
| Married Population | 65.6% | 53.6% | 49.8% |
| Currently Married | 63.5% | 51.3% | 48.0% |
| Married but Separated | 2.1% | 2.3% | 1.8% |
| Single Population | 34.4% | 46.4% | 50.2% |
| Never Married | 23.0% | 24.6% | 33.8% |
| Divorced | 5.9% | 18.2% | 10.8% |
| Widowed | 5.5% | 3.6% | 5.6% |
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| Household Size | 2.91 | 2.55 | 2.60 |
| Households | 878 | 1,853 | 124,010,992 |
| Family Households | 701 | 1,185 | 80,755,759 |
| Married couple, w/children | 35.9% | 35.6% | 30.5% |
| Married couple, no children | 48.5% | 38.3% | 42.9% |
| Non Family Households | 177 | 668 | 43,255,233 |
| Single householder, w/children | 5.4% | 18.7% | 15.8% |
| Single householder, no children | 10.1% | 7.3% | 10.8% |