| | Sierra City, CA | Adin, CA | United States |
| Population | 146 | 171 | 329,725,481 |
| Female Population | 54.1% | 48.0% | 50.5% |
| Male Population | 45.9% | 52.1% | 49.5% |
| Median Age | 72.1 | 67.2 | 38.4 |
| space3 | | | |
| Population - 2010 | 601 | 374 | 309,327,143 |
| Population - 2000 | 230 | 251 | 285,036,114 |
| Population - 1990 | 223 | 249 | 251,960,433 |
| Pop. 2000 to Now | -30.0% | -20.7% | 15.6% |
| Pop. 1990 to Now | -27.8% | -20.1% | 30.8% |
| space4 | | | |
| Population Density | 67.9 | 49.8 | 93.4 |
| Land Area | 2.2 | 3.4 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Sierra City, CA | Adin, CA | United States |
| Age 0 to 4 | 0.0% | 5.3% | 5.9% |
| Age 5 to 9 | 0.0% | 0.0% | 6.1% |
| Age 10 to 14 | 0.0% | 0.0% | 6.6% |
| Age 15 to 17 | 0.0% | 0.0% | 3.9% |
| Age 18 to 20 | 0.0% | 12.3% | 4.0% |
| Age 21 to 24 | 0.0% | 1.2% | 5.2% |
| Age 25 to 34 | 0.0% | 0.0% | 13.8% |
| Age 35 to 44 | 0.0% | 9.4% | 12.9% |
| Age 45 to 54 | 0.0% | 9.9% | 12.6% |
| Age 55 to 59 | 7.5% | 3.5% | 6.7% |
| Age 60 to 64 | 0.0% | 7.6% | 6.3% |
| Age 65 to 74 | 72.6% | 11.1% | 9.6% |
| Age 75 to 84 | 19.9% | 18.7% | 4.5% |
| Age 85 and over | 0.0% | 21.1% | 1.9% |
| space1 | | | |
| Race | | | |
| | Sierra City, CA | Adin, CA | United States |
| White | 100.0% | 82.5% | 59.4% |
| Black | 0.0% | 0.0% | 12.2% |
| Asian | 0.0% | 0.6% | 5.6% |
| Native American | 0.0% | 16.4% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 0.0% | 0.0% | 3.2% |
| Hispanic | 0.0% | 0.6% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Sierra City, CA | Adin, CA | United States |
| Married Population | 93.2% | 45.1% | 49.8% |
| Currently Married | 93.2% | 45.1% | 48.0% |
| Married but Separated | 0.0% | 0.0% | 1.8% |
| Single Population | 6.8% | 54.9% | 50.2% |
| Never Married | 0.0% | 29.0% | 33.8% |
| Divorced | 0.0% | 17.3% | 10.8% |
| Widowed | 6.8% | 8.6% | 5.6% |
| space5 | | | |
| Household Size | 1.92 | 1.73 | 2.60 |
| Households | 76 | 82 | 124,010,992 |
| Family Households | 66 | 43 | 80,755,759 |
| Married couple, w/children | 0.0% | 20.9% | 30.5% |
| Married couple, no children | 100.0% | 79.1% | 42.9% |
| Non Family Households | 10 | 39 | 43,255,233 |
| Single householder, w/children | 0.0% | 0.0% | 15.8% |
| Single householder, no children | 0.0% | 0.0% | 10.8% |