| | Lewiston, CA | Pacifica, CA | United States |
| Population | 1,817 | 38,595 | 329,725,481 |
| Female Population | 53.2% | 49.3% | 50.5% |
| Male Population | 46.8% | 50.7% | 49.5% |
| Median Age | 40.2 | 43.4 | 38.4 |
| space3 | | | |
| Population - 2010 | 1,242 | 37,388 | 309,327,143 |
| Population - 2000 | 1,305 | 38,390 | 285,036,114 |
| Population - 1990 | 1,187 | 37,670 | 251,960,433 |
| Pop. 2000 to Now | -2.2% | -1.0% | 15.6% |
| Pop. 1990 to Now | 7.5% | 0.9% | 30.8% |
| space4 | | | |
| Population Density | 90.8 | 3,049.5 | 93.4 |
| Land Area | 20.0 | 12.7 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Lewiston, CA | Pacifica, CA | United States |
| Age 0 to 4 | 10.5% | 5.3% | 5.9% |
| Age 5 to 9 | 5.2% | 5.0% | 6.1% |
| Age 10 to 14 | 4.2% | 5.5% | 6.6% |
| Age 15 to 17 | 3.2% | 3.7% | 3.9% |
| Age 18 to 20 | 4.9% | 2.0% | 4.0% |
| Age 21 to 24 | 1.6% | 3.8% | 5.2% |
| Age 25 to 34 | 12.4% | 13.1% | 13.8% |
| Age 35 to 44 | 15.0% | 13.5% | 12.9% |
| Age 45 to 54 | 16.8% | 14.7% | 12.6% |
| Age 55 to 59 | 8.3% | 7.4% | 6.7% |
| Age 60 to 64 | 5.1% | 7.0% | 6.3% |
| Age 65 to 74 | 7.2% | 12.2% | 9.6% |
| Age 75 to 84 | 4.7% | 5.4% | 4.5% |
| Age 85 and over | 0.9% | 1.3% | 1.9% |
| space1 | | | |
| Race | | | |
| | Lewiston, CA | Pacifica, CA | United States |
| White | 87.2% | 51.6% | 59.4% |
| Black | 0.1% | 2.3% | 12.2% |
| Asian | 0.6% | 20.5% | 5.6% |
| Native American | 2.2% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 1.1% | 0.2% |
| Other | 0.0% | 0.8% | 0.4% |
| Two or More Races | 7.8% | 5.0% | 3.2% |
| Hispanic | 2.0% | 18.6% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Lewiston, CA | Pacifica, CA | United States |
| Married Population | 44.2% | 54.6% | 49.8% |
| Currently Married | 44.2% | 52.9% | 48.0% |
| Married but Separated | 0.0% | 1.7% | 1.8% |
| Single Population | 55.8% | 45.4% | 50.2% |
| Never Married | 24.3% | 30.6% | 33.8% |
| Divorced | 25.2% | 9.9% | 10.8% |
| Widowed | 6.3% | 5.0% | 5.6% |
| space5 | | | |
| Household Size | 3.63 | 2.75 | 2.60 |
| Households | 500 | 13,986 | 124,010,992 |
| Family Households | 378 | 9,971 | 80,755,759 |
| Married couple, w/children | 22.5% | 30.9% | 30.5% |
| Married couple, no children | 41.0% | 47.3% | 42.9% |
| Non Family Households | 122 | 4,015 | 43,255,233 |
| Single householder, w/children | 29.1% | 10.0% | 15.8% |
| Single householder, no children | 7.4% | 11.7% | 10.8% |