| | Leonardtown, MD | Palmdale, CA | United States |
| Population | 4,445 | 167,987 | 329,725,481 |
| Female Population | 46.8% | 50.6% | 50.5% |
| Male Population | 53.2% | 49.4% | 49.5% |
| Median Age | 32.3 | 32.6 | 38.4 |
| space3 | | | |
| Population - 2010 | 3,015 | 152,761 | 309,327,143 |
| Population - 2000 | 1,896 | 116,670 | 285,036,114 |
| Population - 1990 | 1,475 | 68,842 | 251,960,433 |
| Pop. 2000 to Now | 106.3% | 29.0% | 15.6% |
| Pop. 1990 to Now | 165.2% | 118.6% | 30.8% |
| space4 | | | |
| Population Density | 1,168.5 | 1,583.7 | 93.4 |
| Land Area | 3.8 | 106.1 | 3,531,905.4 |
| Water Area | 0.1 | 0.2 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Leonardtown, MD | Palmdale, CA | United States |
| Age 0 to 4 | 6.8% | 7.5% | 5.9% |
| Age 5 to 9 | 7.6% | 7.9% | 6.1% |
| Age 10 to 14 | 11.6% | 8.9% | 6.6% |
| Age 15 to 17 | 3.6% | 5.4% | 3.9% |
| Age 18 to 20 | 4.6% | 4.3% | 4.0% |
| Age 21 to 24 | 8.2% | 5.8% | 5.2% |
| Age 25 to 34 | 12.1% | 13.2% | 13.8% |
| Age 35 to 44 | 16.5% | 12.9% | 12.9% |
| Age 45 to 54 | 12.3% | 12.5% | 12.6% |
| Age 55 to 59 | 4.2% | 6.2% | 6.7% |
| Age 60 to 64 | 2.1% | 5.3% | 6.3% |
| Age 65 to 74 | 5.3% | 6.6% | 9.6% |
| Age 75 to 84 | 2.5% | 2.6% | 4.5% |
| Age 85 and over | 2.5% | 0.9% | 1.9% |
| space1 | | | |
| Race | | | |
| | Leonardtown, MD | Palmdale, CA | United States |
| White | 69.7% | 18.9% | 59.4% |
| Black | 6.1% | 12.4% | 12.2% |
| Asian | 5.9% | 4.3% | 5.6% |
| Native American | 0.0% | 0.7% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.2% | 0.2% |
| Other | 1.1% | 0.5% | 0.4% |
| Two or More Races | 3.2% | 1.9% | 3.2% |
| Hispanic | 14.0% | 61.0% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Leonardtown, MD | Palmdale, CA | United States |
| Married Population | 44.7% | 48.5% | 49.8% |
| Currently Married | 42.4% | 46.0% | 48.0% |
| Married but Separated | 2.3% | 2.4% | 1.8% |
| Single Population | 55.3% | 51.5% | 50.2% |
| Never Married | 37.4% | 40.6% | 33.8% |
| Divorced | 11.9% | 7.2% | 10.8% |
| Widowed | 6.0% | 3.7% | 5.6% |
| space5 | | | |
| Household Size | 2.75 | 3.61 | 2.60 |
| Households | 1,457 | 46,515 | 124,010,992 |
| Family Households | 837 | 37,630 | 80,755,759 |
| Married couple, w/children | 66.2% | 35.8% | 30.5% |
| Married couple, no children | 13.9% | 30.7% | 42.9% |
| Non Family Households | 620 | 8,885 | 43,255,233 |
| Single householder, w/children | 16.1% | 22.0% | 15.8% |
| Single householder, no children | 3.8% | 11.5% | 10.8% |