| | Cobb, CA | Colfax, CA | United States |
| Population | 646 | 2,289 | 329,725,481 |
| Female Population | 27.6% | 47.0% | 50.5% |
| Male Population | 72.5% | 53.0% | 49.5% |
| Median Age | 54.5 | 35.6 | 38.4 |
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| Population - 2010 | 1,938 | 1,948 | 309,327,143 |
| Population - 2000 | 1,638 | 1,496 | 285,036,114 |
| Population - 1990 | 1,477 | 1,306 | 251,960,433 |
| Pop. 2000 to Now | -39.7% | 34.3% | 15.6% |
| Pop. 1990 to Now | -33.2% | 53.8% | 30.8% |
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| Population Density | 129.7 | 1,628.0 | 93.4 |
| Land Area | 5.0 | 1.4 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Cobb, CA | Colfax, CA | United States |
| Age 0 to 4 | 0.0% | 4.5% | 5.9% |
| Age 5 to 9 | 0.0% | 8.5% | 6.1% |
| Age 10 to 14 | 0.0% | 8.3% | 6.6% |
| Age 15 to 17 | 5.3% | 7.4% | 3.9% |
| Age 18 to 20 | 0.0% | 4.0% | 4.0% |
| Age 21 to 24 | 0.0% | 4.8% | 5.2% |
| Age 25 to 34 | 0.0% | 10.9% | 13.8% |
| Age 35 to 44 | 28.9% | 20.4% | 12.9% |
| Age 45 to 54 | 17.5% | 9.8% | 12.6% |
| Age 55 to 59 | 3.9% | 3.9% | 6.7% |
| Age 60 to 64 | 17.2% | 5.9% | 6.3% |
| Age 65 to 74 | 19.4% | 5.8% | 9.6% |
| Age 75 to 84 | 3.9% | 3.5% | 4.5% |
| Age 85 and over | 4.0% | 2.4% | 1.9% |
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| Race | | | |
| | Cobb, CA | Colfax, CA | United States |
| White | 100.0% | 78.8% | 59.4% |
| Black | 0.0% | 3.2% | 12.2% |
| Asian | 0.0% | 0.9% | 5.6% |
| Native American | 0.0% | 0.7% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 1.2% | 0.4% |
| Two or More Races | 0.0% | 1.7% | 3.2% |
| Hispanic | 0.0% | 13.5% | 18.4% |
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| Marriage & Family | | | |
| | Cobb, CA | Colfax, CA | United States |
| Married Population | 57.6% | 44.2% | 49.8% |
| Currently Married | 55.3% | 42.6% | 48.0% |
| Married but Separated | 2.3% | 1.6% | 1.8% |
| Single Population | 42.4% | 55.8% | 50.2% |
| Never Married | 16.9% | 34.4% | 33.8% |
| Divorced | 16.9% | 15.9% | 10.8% |
| Widowed | 8.7% | 5.5% | 5.6% |
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| Household Size | 1.67 | 2.65 | 2.60 |
| Households | 387 | 865 | 124,010,992 |
| Family Households | 230 | 508 | 80,755,759 |
| Married couple, w/children | 0.0% | 51.2% | 30.5% |
| Married couple, no children | 74.8% | 24.2% | 42.9% |
| Non Family Households | 157 | 357 | 43,255,233 |
| Single householder, w/children | 13.9% | 13.0% | 15.8% |
| Single householder, no children | 11.3% | 11.6% | 10.8% |