| | Oceano, CA | Marina, CA | United States |
| Population | 7,371 | 22,246 | 329,725,481 |
| Female Population | 50.0% | 51.4% | 50.5% |
| Male Population | 50.0% | 48.6% | 49.5% |
| Median Age | 44.8 | 34.9 | 38.4 |
| space3 | | | |
| Population - 2010 | 7,883 | 19,731 | 309,327,143 |
| Population - 2000 | 7,260 | 25,101 | 285,036,114 |
| Population - 1990 | 6,169 | 26,436 | 251,960,433 |
| Pop. 2000 to Now | 8.1% | -13.0% | 15.6% |
| Pop. 1990 to Now | 27.2% | -17.4% | 30.8% |
| space4 | | | |
| Population Density | 4,811.4 | 2,502.6 | 93.4 |
| Land Area | 1.5 | 8.9 | 3,531,905.4 |
| Water Area | 0.0 | 0.9 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Oceano, CA | Marina, CA | United States |
| Age 0 to 4 | 6.8% | 6.3% | 5.9% |
| Age 5 to 9 | 5.8% | 5.9% | 6.1% |
| Age 10 to 14 | 5.2% | 5.2% | 6.6% |
| Age 15 to 17 | 4.1% | 3.3% | 3.9% |
| Age 18 to 20 | 0.8% | 6.1% | 4.0% |
| Age 21 to 24 | 2.9% | 8.4% | 5.2% |
| Age 25 to 34 | 12.6% | 15.1% | 13.8% |
| Age 35 to 44 | 12.3% | 11.6% | 12.9% |
| Age 45 to 54 | 13.9% | 10.6% | 12.6% |
| Age 55 to 59 | 3.2% | 6.4% | 6.7% |
| Age 60 to 64 | 5.1% | 6.6% | 6.3% |
| Age 65 to 74 | 14.6% | 8.4% | 9.6% |
| Age 75 to 84 | 8.4% | 4.9% | 4.5% |
| Age 85 and over | 4.2% | 1.3% | 1.9% |
| space1 | | | |
| Race | | | |
| | Oceano, CA | Marina, CA | United States |
| White | 49.4% | 38.4% | 59.4% |
| Black | 1.9% | 6.6% | 12.2% |
| Asian | 2.1% | 15.5% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 2.0% | 0.2% |
| Other | 0.0% | 0.5% | 0.4% |
| Two or More Races | 3.7% | 8.7% | 3.2% |
| Hispanic | 42.9% | 28.3% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Oceano, CA | Marina, CA | United States |
| Married Population | 53.8% | 46.0% | 49.8% |
| Currently Married | 51.0% | 44.2% | 48.0% |
| Married but Separated | 2.8% | 1.8% | 1.8% |
| Single Population | 46.2% | 54.0% | 50.2% |
| Never Married | 24.2% | 39.8% | 33.8% |
| Divorced | 16.7% | 9.5% | 10.8% |
| Widowed | 5.4% | 4.6% | 5.6% |
| space5 | | | |
| Household Size | 2.49 | 2.72 | 2.60 |
| Households | 2,958 | 7,676 | 124,010,992 |
| Family Households | 1,783 | 4,925 | 80,755,759 |
| Married couple, w/children | 30.8% | 31.1% | 30.5% |
| Married couple, no children | 41.1% | 41.0% | 42.9% |
| Non Family Households | 1,175 | 2,751 | 43,255,233 |
| Single householder, w/children | 18.6% | 14.4% | 15.8% |
| Single householder, no children | 9.5% | 13.5% | 10.8% |