| | Foster City, CA | Huntington Beach, CA | United States |
| Population | 33,511 | 198,735 | 329,725,481 |
| Female Population | 50.8% | 49.6% | 50.5% |
| Male Population | 49.3% | 50.4% | 49.5% |
| Median Age | 39.6 | 43.1 | 38.4 |
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| Population - 2010 | 30,597 | 191,080 | 309,327,143 |
| Population - 2000 | 28,803 | 189,594 | 285,036,114 |
| Population - 1990 | 28,176 | 181,519 | 251,960,433 |
| Pop. 2000 to Now | 14.2% | 4.6% | 15.6% |
| Pop. 1990 to Now | 16.7% | 9.2% | 30.8% |
| space4 | | | |
| Population Density | 8,828.0 | 7,359.7 | 93.4 |
| Land Area | 3.8 | 27.0 | 3,531,905.4 |
| Water Area | 16.0 | 5.1 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Foster City, CA | Huntington Beach, CA | United States |
| Age 0 to 4 | 5.6% | 5.1% | 5.9% |
| Age 5 to 9 | 7.2% | 4.6% | 6.1% |
| Age 10 to 14 | 5.9% | 5.5% | 6.6% |
| Age 15 to 17 | 3.9% | 3.5% | 3.9% |
| Age 18 to 20 | 1.8% | 2.9% | 4.0% |
| Age 21 to 24 | 2.7% | 4.6% | 5.2% |
| Age 25 to 34 | 15.4% | 14.1% | 13.8% |
| Age 35 to 44 | 16.9% | 12.5% | 12.9% |
| Age 45 to 54 | 12.7% | 14.3% | 12.6% |
| Age 55 to 59 | 5.8% | 7.8% | 6.7% |
| Age 60 to 64 | 5.2% | 6.8% | 6.3% |
| Age 65 to 74 | 8.5% | 10.6% | 9.6% |
| Age 75 to 84 | 6.0% | 5.5% | 4.5% |
| Age 85 and over | 2.5% | 2.1% | 1.9% |
| space1 | | | |
| Race | | | |
| | Foster City, CA | Huntington Beach, CA | United States |
| White | 31.0% | 60.2% | 59.4% |
| Black | 2.4% | 1.1% | 12.2% |
| Asian | 51.8% | 12.6% | 5.6% |
| Native American | 0.2% | 0.2% | 0.6% |
| Hawaiian, Pacific Islander | 0.2% | 0.3% | 0.2% |
| Other | 0.1% | 0.5% | 0.4% |
| Two or More Races | 5.6% | 5.2% | 3.2% |
| Hispanic | 8.6% | 19.8% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Foster City, CA | Huntington Beach, CA | United States |
| Married Population | 62.4% | 49.3% | 49.8% |
| Currently Married | 61.1% | 48.0% | 48.0% |
| Married but Separated | 1.2% | 1.3% | 1.8% |
| Single Population | 37.6% | 50.7% | 50.2% |
| Never Married | 25.6% | 34.1% | 33.8% |
| Divorced | 6.2% | 12.0% | 10.8% |
| Widowed | 5.8% | 4.7% | 5.6% |
| space5 | | | |
| Household Size | 2.67 | 2.56 | 2.60 |
| Households | 12,475 | 77,143 | 124,010,992 |
| Family Households | 8,857 | 49,631 | 80,755,759 |
| Married couple, w/children | 44.2% | 29.0% | 30.5% |
| Married couple, no children | 40.5% | 45.8% | 42.9% |
| Non Family Households | 3,618 | 27,512 | 43,255,233 |
| Single householder, w/children | 7.8% | 11.1% | 15.8% |
| Single householder, no children | 7.6% | 14.1% | 10.8% |