| | Mokelumne Hill, CA | El Sobrante (Contra Costa County), CA | United States |
| Population | 680 | 15,468 | 329,725,481 |
| Female Population | 58.5% | 51.9% | 50.5% |
| Male Population | 41.5% | 48.1% | 49.5% |
| Median Age | 61.2 | 40.7 | 38.4 |
| space3 | | | |
| Population - 2010 | 736 | 13,489 | 309,327,143 |
| Population - 2000 | 774 | 12,260 | 285,036,114 |
| Population - 1990 | 542 | 9,852 | 251,960,433 |
| Pop. 2000 to Now | -19.6% | 11.7% | 15.6% |
| Pop. 1990 to Now | 14.8% | 39.0% | 30.8% |
| space4 | | | |
| Population Density | 220.9 | 5,594.2 | 93.4 |
| Land Area | 3.1 | 2.8 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Mokelumne Hill, CA | El Sobrante (Contra Costa County), CA | United States |
| Age 0 to 4 | 3.4% | 5.3% | 5.9% |
| Age 5 to 9 | 0.0% | 6.1% | 6.1% |
| Age 10 to 14 | 0.0% | 5.4% | 6.6% |
| Age 15 to 17 | 4.0% | 3.5% | 3.9% |
| Age 18 to 20 | 0.0% | 1.7% | 4.0% |
| Age 21 to 24 | 0.0% | 4.7% | 5.2% |
| Age 25 to 34 | 8.4% | 14.1% | 13.8% |
| Age 35 to 44 | 10.6% | 14.3% | 12.9% |
| Age 45 to 54 | 11.6% | 15.3% | 12.6% |
| Age 55 to 59 | 9.9% | 7.4% | 6.7% |
| Age 60 to 64 | 32.4% | 5.0% | 6.3% |
| Age 65 to 74 | 14.6% | 12.1% | 9.6% |
| Age 75 to 84 | 2.9% | 3.3% | 4.5% |
| Age 85 and over | 2.4% | 1.9% | 1.9% |
| space1 | | | |
| Race | | | |
| | Mokelumne Hill, CA | El Sobrante (Contra Costa County), CA | United States |
| White | 56.8% | 37.5% | 59.4% |
| Black | 20.7% | 8.8% | 12.2% |
| Asian | 0.0% | 17.4% | 5.6% |
| Native American | 0.0% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 1.5% | 0.2% |
| Other | 0.0% | 0.1% | 0.4% |
| Two or More Races | 0.0% | 6.0% | 3.2% |
| Hispanic | 22.5% | 28.6% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Mokelumne Hill, CA | El Sobrante (Contra Costa County), CA | United States |
| Married Population | 71.2% | 50.9% | 49.8% |
| Currently Married | 71.2% | 49.4% | 48.0% |
| Married but Separated | 0.0% | 1.5% | 1.8% |
| Single Population | 28.8% | 49.1% | 50.2% |
| Never Married | 21.5% | 35.6% | 33.8% |
| Divorced | 4.9% | 8.6% | 10.8% |
| Widowed | 2.4% | 4.8% | 5.6% |
| space5 | | | |
| Household Size | 2.13 | 2.89 | 2.60 |
| Households | 320 | 5,328 | 124,010,992 |
| Family Households | 288 | 4,027 | 80,755,759 |
| Married couple, w/children | 7.6% | 29.5% | 30.5% |
| Married couple, no children | 92.4% | 41.3% | 42.9% |
| Non Family Households | 32 | 1,301 | 43,255,233 |
| Single householder, w/children | 0.0% | 15.6% | 15.8% |
| Single householder, no children | 0.0% | 13.5% | 10.8% |