| | Bel Air North, MD | Roseville, CA | United States |
| Population | 30,969 | 145,687 | 329,725,481 |
| Female Population | 49.9% | 51.1% | 50.5% |
| Male Population | 50.1% | 48.9% | 49.5% |
| Median Age | 39.9 | 39.2 | 38.4 |
| space3 | | | |
| Population - 2010 | 29,172 | 119,960 | 309,327,143 |
| Population - 2000 | 25,798 | 79,921 | 285,036,114 |
| Population - 1990 | 14,880 | 44,685 | 251,960,433 |
| Pop. 2000 to Now | 24.6% | 81.1% | 15.6% |
| Pop. 1990 to Now | 116.1% | 223.9% | 30.8% |
| space4 | | | |
| Population Density | 1,940.3 | 3,382.6 | 93.4 |
| Land Area | 16.0 | 43.1 | 3,531,905.4 |
| Water Area | 0.1 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Bel Air North, MD | Roseville, CA | United States |
| Age 0 to 4 | 6.0% | 6.0% | 5.9% |
| Age 5 to 9 | 7.3% | 6.0% | 6.1% |
| Age 10 to 14 | 7.8% | 7.1% | 6.6% |
| Age 15 to 17 | 4.5% | 4.3% | 3.9% |
| Age 18 to 20 | 3.1% | 3.3% | 4.0% |
| Age 21 to 24 | 4.1% | 4.3% | 5.2% |
| Age 25 to 34 | 10.3% | 12.9% | 13.8% |
| Age 35 to 44 | 13.1% | 14.3% | 12.9% |
| Age 45 to 54 | 16.7% | 13.3% | 12.6% |
| Age 55 to 59 | 6.6% | 6.6% | 6.7% |
| Age 60 to 64 | 5.9% | 5.6% | 6.3% |
| Age 65 to 74 | 8.3% | 9.1% | 9.6% |
| Age 75 to 84 | 4.4% | 4.7% | 4.5% |
| Age 85 and over | 1.8% | 2.4% | 1.9% |
| space1 | | | |
| Race | | | |
| | Bel Air North, MD | Roseville, CA | United States |
| White | 89.4% | 65.2% | 59.4% |
| Black | 2.9% | 2.0% | 12.2% |
| Asian | 1.6% | 11.8% | 5.6% |
| Native American | 0.0% | 0.2% | 0.6% |
| Hawaiian, Pacific Islander | 0.1% | 0.2% | 0.2% |
| Other | 0.0% | 0.2% | 0.4% |
| Two or More Races | 3.7% | 4.7% | 3.2% |
| Hispanic | 2.4% | 15.8% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Bel Air North, MD | Roseville, CA | United States |
| Married Population | 65.6% | 55.7% | 49.8% |
| Currently Married | 64.5% | 54.2% | 48.0% |
| Married but Separated | 1.2% | 1.6% | 1.8% |
| Single Population | 34.4% | 44.3% | 50.2% |
| Never Married | 23.8% | 27.7% | 33.8% |
| Divorced | 5.2% | 11.1% | 10.8% |
| Widowed | 5.4% | 5.4% | 5.6% |
| space5 | | | |
| Household Size | 2.81 | 2.65 | 2.60 |
| Households | 10,815 | 54,571 | 124,010,992 |
| Family Households | 8,662 | 38,429 | 80,755,759 |
| Married couple, w/children | 43.9% | 36.9% | 30.5% |
| Married couple, no children | 45.8% | 41.3% | 42.9% |
| Non Family Households | 2,153 | 16,142 | 43,255,233 |
| Single householder, w/children | 5.5% | 12.2% | 15.8% |
| Single householder, no children | 4.8% | 9.7% | 10.8% |