| | Hayfork, CA | Derby Acres, CA | United States |
| Population | 3,639 | 362 | 329,725,481 |
| Female Population | 49.6% | 45.6% | 50.5% |
| Male Population | 50.5% | 54.4% | 49.5% |
| Median Age | 52.7 | 45.1 | 38.4 |
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| Population - 2010 | 2,055 | 401 | 309,327,143 |
| Population - 2000 | 2,315 | 376 | 285,036,114 |
| Population - 1990 | 2,605 | 334 | 251,960,433 |
| Pop. 2000 to Now | 6.4% | -12.5% | 15.6% |
| Pop. 1990 to Now | -5.4% | -1.5% | 30.8% |
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| Population Density | 50.5 | 101.1 | 93.4 |
| Land Area | 72.1 | 3.6 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Hayfork, CA | Derby Acres, CA | United States |
| Age 0 to 4 | 3.2% | 7.2% | 5.9% |
| Age 5 to 9 | 6.2% | 6.6% | 6.1% |
| Age 10 to 14 | 4.0% | 9.4% | 6.6% |
| Age 15 to 17 | 2.6% | 1.7% | 3.9% |
| Age 18 to 20 | 1.0% | 2.8% | 4.0% |
| Age 21 to 24 | 2.4% | 4.1% | 5.2% |
| Age 25 to 34 | 15.9% | 13.0% | 13.8% |
| Age 35 to 44 | 4.2% | 5.0% | 12.9% |
| Age 45 to 54 | 12.2% | 15.5% | 12.6% |
| Age 55 to 59 | 3.4% | 12.2% | 6.7% |
| Age 60 to 64 | 20.6% | 5.0% | 6.3% |
| Age 65 to 74 | 11.9% | 9.9% | 9.6% |
| Age 75 to 84 | 4.6% | 6.6% | 4.5% |
| Age 85 and over | 7.7% | 1.1% | 1.9% |
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| Race | | | |
| | Hayfork, CA | Derby Acres, CA | United States |
| White | 78.1% | 64.6% | 59.4% |
| Black | 1.9% | 0.0% | 12.2% |
| Asian | 2.4% | 0.0% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 5.1% | 7.7% | 3.2% |
| Hispanic | 12.5% | 27.6% | 18.4% |
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| Marriage & Family | | | |
| | Hayfork, CA | Derby Acres, CA | United States |
| Married Population | 23.4% | 46.0% | 49.8% |
| Currently Married | 22.3% | 43.2% | 48.0% |
| Married but Separated | 1.0% | 2.9% | 1.8% |
| Single Population | 76.7% | 54.0% | 50.2% |
| Never Married | 25.9% | 19.8% | 33.8% |
| Divorced | 42.9% | 13.0% | 10.8% |
| Widowed | 7.8% | 21.2% | 5.6% |
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| Household Size | 3.65 | 2.97 | 2.60 |
| Households | 991 | 122 | 124,010,992 |
| Family Households | 395 | 92 | 80,755,759 |
| Married couple, w/children | 7.8% | 20.7% | 30.5% |
| Married couple, no children | 64.8% | 37.0% | 42.9% |
| Non Family Households | 596 | 30 | 43,255,233 |
| Single householder, w/children | 12.2% | 27.2% | 15.8% |
| Single householder, no children | 15.2% | 15.2% | 10.8% |