| | La Plata, MD | California, MD | United States |
| Population | 10,054 | 14,129 | 329,725,481 |
| Female Population | 48.1% | 50.0% | 50.5% |
| Male Population | 52.0% | 50.0% | 49.5% |
| Median Age | 42.6 | 35.6 | 38.4 |
| space3 | | | |
| Population - 2010 | 8,805 | 11,970 | 309,327,143 |
| Population - 2000 | 6,551 | 9,307 | 285,036,114 |
| Population - 1990 | 5,841 | 7,626 | 251,960,433 |
| Pop. 2000 to Now | 49.6% | 49.1% | 15.6% |
| Pop. 1990 to Now | 67.8% | 81.9% | 30.8% |
| space4 | | | |
| Population Density | 1,352.8 | 1,097.7 | 93.4 |
| Land Area | 7.4 | 12.9 | 3,531,905.4 |
| Water Area | 0.1 | 2.1 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | La Plata, MD | California, MD | United States |
| Age 0 to 4 | 4.2% | 5.1% | 5.9% |
| Age 5 to 9 | 5.2% | 6.0% | 6.1% |
| Age 10 to 14 | 8.0% | 9.1% | 6.6% |
| Age 15 to 17 | 3.5% | 5.3% | 3.9% |
| Age 18 to 20 | 3.7% | 4.2% | 4.0% |
| Age 21 to 24 | 4.5% | 3.9% | 5.2% |
| Age 25 to 34 | 10.1% | 15.3% | 13.8% |
| Age 35 to 44 | 13.5% | 13.7% | 12.9% |
| Age 45 to 54 | 15.7% | 15.7% | 12.6% |
| Age 55 to 59 | 11.2% | 6.7% | 6.7% |
| Age 60 to 64 | 5.0% | 5.1% | 6.3% |
| Age 65 to 74 | 9.2% | 6.4% | 9.6% |
| Age 75 to 84 | 4.7% | 2.8% | 4.5% |
| Age 85 and over | 1.4% | 0.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | La Plata, MD | California, MD | United States |
| White | 58.2% | 63.3% | 59.4% |
| Black | 28.7% | 24.1% | 12.2% |
| Asian | 4.5% | 3.6% | 5.6% |
| Native American | 0.1% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.6% | 0.4% |
| Two or More Races | 3.5% | 3.2% | 3.2% |
| Hispanic | 5.1% | 4.9% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | La Plata, MD | California, MD | United States |
| Married Population | 48.5% | 53.5% | 49.8% |
| Currently Married | 45.9% | 51.5% | 48.0% |
| Married but Separated | 2.6% | 2.1% | 1.8% |
| Single Population | 51.5% | 46.5% | 50.2% |
| Never Married | 31.9% | 32.7% | 33.8% |
| Divorced | 11.2% | 8.9% | 10.8% |
| Widowed | 8.4% | 4.8% | 5.6% |
| space5 | | | |
| Household Size | 2.68 | 2.64 | 2.60 |
| Households | 3,448 | 5,343 | 124,010,992 |
| Family Households | 2,237 | 3,609 | 80,755,759 |
| Married couple, w/children | 40.3% | 36.4% | 30.5% |
| Married couple, no children | 37.1% | 39.7% | 42.9% |
| Non Family Households | 1,211 | 1,734 | 43,255,233 |
| Single householder, w/children | 14.6% | 16.9% | 15.8% |
| Single householder, no children | 8.0% | 6.9% | 10.8% |