| | Rohnert Park, CA | Fair Oaks, CA | United States |
| Population | 44,420 | 31,750 | 329,725,481 |
| Female Population | 51.9% | 51.3% | 50.5% |
| Male Population | 48.1% | 48.8% | 49.5% |
| Median Age | 35.3 | 46.2 | 38.4 |
| space3 | | | |
| Population - 2010 | 41,110 | 30,715 | 309,327,143 |
| Population - 2000 | 42,236 | 28,008 | 285,036,114 |
| Population - 1990 | 36,326 | 26,867 | 251,960,433 |
| Pop. 2000 to Now | 1.8% | 14.4% | 15.6% |
| Pop. 1990 to Now | 18.3% | 19.3% | 30.8% |
| space4 | | | |
| Population Density | 6,343.0 | 2,919.3 | 93.4 |
| Land Area | 7.0 | 10.9 | 3,531,905.4 |
| Water Area | 0.0 | 0.3 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Rohnert Park, CA | Fair Oaks, CA | United States |
| Age 0 to 4 | 6.3% | 4.2% | 5.9% |
| Age 5 to 9 | 5.7% | 5.6% | 6.1% |
| Age 10 to 14 | 5.1% | 5.8% | 6.6% |
| Age 15 to 17 | 3.1% | 3.7% | 3.9% |
| Age 18 to 20 | 3.9% | 2.8% | 4.0% |
| Age 21 to 24 | 9.3% | 3.2% | 5.2% |
| Age 25 to 34 | 16.2% | 12.1% | 13.8% |
| Age 35 to 44 | 12.8% | 11.2% | 12.9% |
| Age 45 to 54 | 10.8% | 13.8% | 12.6% |
| Age 55 to 59 | 6.3% | 7.2% | 6.7% |
| Age 60 to 64 | 6.2% | 7.4% | 6.3% |
| Age 65 to 74 | 9.4% | 14.7% | 9.6% |
| Age 75 to 84 | 3.0% | 6.1% | 4.5% |
| Age 85 and over | 2.0% | 2.4% | 1.9% |
| space1 | | | |
| Race | | | |
| | Rohnert Park, CA | Fair Oaks, CA | United States |
| White | 56.7% | 72.8% | 59.4% |
| Black | 3.1% | 2.0% | 12.2% |
| Asian | 6.2% | 5.2% | 5.6% |
| Native American | 0.5% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.7% | 0.0% | 0.2% |
| Other | 0.4% | 0.0% | 0.4% |
| Two or More Races | 4.1% | 5.7% | 3.2% |
| Hispanic | 28.3% | 14.1% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Rohnert Park, CA | Fair Oaks, CA | United States |
| Married Population | 41.8% | 54.3% | 49.8% |
| Currently Married | 40.6% | 52.1% | 48.0% |
| Married but Separated | 1.2% | 2.2% | 1.8% |
| Single Population | 58.2% | 45.7% | 50.2% |
| Never Married | 42.5% | 27.2% | 33.8% |
| Divorced | 11.5% | 13.4% | 10.8% |
| Widowed | 4.2% | 5.1% | 5.6% |
| space5 | | | |
| Household Size | 2.58 | 2.43 | 2.60 |
| Households | 17,186 | 12,846 | 124,010,992 |
| Family Households | 10,184 | 8,379 | 80,755,759 |
| Married couple, w/children | 24.7% | 24.6% | 30.5% |
| Married couple, no children | 42.6% | 52.2% | 42.9% |
| Non Family Households | 7,002 | 4,467 | 43,255,233 |
| Single householder, w/children | 22.1% | 14.2% | 15.8% |
| Single householder, no children | 10.6% | 8.9% | 10.8% |