| | Atglen, PA | Baltimore, MD | United States |
| Population | 1,202 | 592,211 | 329,725,481 |
| Female Population | 54.9% | 52.9% | 50.5% |
| Male Population | 45.1% | 47.1% | 49.5% |
| Median Age | 32.3 | 35.7 | 38.4 |
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| Population - 2010 | 1,409 | 620,942 | 309,327,143 |
| Population - 2000 | 1,217 | 651,154 | 285,036,114 |
| Population - 1990 | 825 | 736,014 | 251,960,433 |
| Pop. 2000 to Now | 15.3% | -10.0% | 15.6% |
| Pop. 1990 to Now | 70.1% | -20.4% | 30.8% |
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| Population Density | 1,373.7 | 7,316.1 | 93.4 |
| Land Area | 0.9 | 80.9 | 3,531,905.4 |
| Water Area | 0.0 | 11.1 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Atglen, PA | Baltimore, MD | United States |
| Age 0 to 4 | 9.6% | 6.2% | 5.9% |
| Age 5 to 9 | 4.5% | 5.5% | 6.1% |
| Age 10 to 14 | 8.6% | 5.7% | 6.6% |
| Age 15 to 17 | 3.5% | 3.1% | 3.9% |
| Age 18 to 20 | 6.3% | 4.3% | 4.0% |
| Age 21 to 24 | 7.2% | 5.1% | 5.2% |
| Age 25 to 34 | 13.3% | 18.8% | 13.8% |
| Age 35 to 44 | 7.7% | 13.0% | 12.9% |
| Age 45 to 54 | 16.1% | 11.4% | 12.6% |
| Age 55 to 59 | 7.7% | 6.4% | 6.7% |
| Age 60 to 64 | 7.4% | 6.4% | 6.3% |
| Age 65 to 74 | 4.2% | 8.7% | 9.6% |
| Age 75 to 84 | 1.1% | 3.8% | 4.5% |
| Age 85 and over | 2.7% | 1.6% | 1.9% |
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| Race | | | |
| | Atglen, PA | Baltimore, MD | United States |
| White | 76.0% | 27.3% | 59.4% |
| Black | 8.1% | 60.9% | 12.2% |
| Asian | 0.4% | 2.5% | 5.6% |
| Native American | 0.0% | 0.2% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.4% | 0.4% |
| Two or More Races | 2.1% | 3.0% | 3.2% |
| Hispanic | 13.4% | 5.6% | 18.4% |
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| Marriage & Family | | | |
| | Atglen, PA | Baltimore, MD | United States |
| Married Population | 44.7% | 30.3% | 49.8% |
| Currently Married | 44.7% | 27.2% | 48.0% |
| Married but Separated | 0.0% | 3.1% | 1.8% |
| Single Population | 55.3% | 69.7% | 50.2% |
| Never Married | 40.2% | 52.3% | 33.8% |
| Divorced | 11.3% | 11.4% | 10.8% |
| Widowed | 3.8% | 6.0% | 5.6% |
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| Household Size | 2.86 | 2.32 | 2.60 |
| Households | 420 | 244,893 | 124,010,992 |
| Family Households | 330 | 119,410 | 80,755,759 |
| Married couple, w/children | 28.8% | 18.6% | 30.5% |
| Married couple, no children | 33.0% | 30.5% | 42.9% |
| Non Family Households | 90 | 125,483 | 43,255,233 |
| Single householder, w/children | 29.4% | 29.1% | 15.8% |
| Single householder, no children | 8.8% | 21.8% | 10.8% |