| | Oak Park, CA | San Dimas, CA | United States |
| Population | 13,561 | 34,775 | 329,725,481 |
| Female Population | 52.0% | 53.1% | 50.5% |
| Male Population | 48.0% | 46.9% | 49.5% |
| Median Age | 42.9 | 42.6 | 38.4 |
| space3 | | | |
| Population - 2010 | 14,044 | 33,369 | 309,327,143 |
| Population - 2000 | 2,320 | 34,980 | 285,036,114 |
| Population - 1990 | 2,412 | 32,397 | 251,960,433 |
| Pop. 2000 to Now | 519.3% | -5.2% | 15.6% |
| Pop. 1990 to Now | 495.7% | 2.4% | 30.8% |
| space4 | | | |
| Population Density | 2,561.6 | 2,312.5 | 93.4 |
| Land Area | 5.3 | 15.0 | 3,531,905.4 |
| Water Area | 0.0 | 0.4 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Oak Park, CA | San Dimas, CA | United States |
| Age 0 to 4 | 6.2% | 5.0% | 5.9% |
| Age 5 to 9 | 5.3% | 5.4% | 6.1% |
| Age 10 to 14 | 8.4% | 6.3% | 6.6% |
| Age 15 to 17 | 5.3% | 3.8% | 3.9% |
| Age 18 to 20 | 3.2% | 4.2% | 4.0% |
| Age 21 to 24 | 3.8% | 3.5% | 5.2% |
| Age 25 to 34 | 6.6% | 12.5% | 13.8% |
| Age 35 to 44 | 13.7% | 11.1% | 12.9% |
| Age 45 to 54 | 15.6% | 14.4% | 12.6% |
| Age 55 to 59 | 10.1% | 7.4% | 6.7% |
| Age 60 to 64 | 6.2% | 7.2% | 6.3% |
| Age 65 to 74 | 10.4% | 11.9% | 9.6% |
| Age 75 to 84 | 2.6% | 5.6% | 4.5% |
| Age 85 and over | 2.4% | 1.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Oak Park, CA | San Dimas, CA | United States |
| White | 69.1% | 41.8% | 59.4% |
| Black | 0.9% | 2.7% | 12.2% |
| Asian | 17.7% | 16.1% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.1% | 0.2% | 0.2% |
| Other | 0.5% | 0.3% | 0.4% |
| Two or More Races | 3.2% | 4.3% | 3.2% |
| Hispanic | 8.5% | 34.5% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Oak Park, CA | San Dimas, CA | United States |
| Married Population | 59.5% | 53.2% | 49.8% |
| Currently Married | 58.8% | 52.2% | 48.0% |
| Married but Separated | 0.6% | 1.0% | 1.8% |
| Single Population | 40.5% | 46.8% | 50.2% |
| Never Married | 25.6% | 29.0% | 33.8% |
| Divorced | 9.8% | 11.1% | 10.8% |
| Widowed | 5.1% | 6.8% | 5.6% |
| space5 | | | |
| Household Size | 2.70 | 2.88 | 2.60 |
| Households | 5,018 | 11,812 | 124,010,992 |
| Family Households | 3,478 | 8,784 | 80,755,759 |
| Married couple, w/children | 45.8% | 30.7% | 30.5% |
| Married couple, no children | 43.5% | 43.8% | 42.9% |
| Non Family Households | 1,540 | 3,028 | 43,255,233 |
| Single householder, w/children | 5.0% | 10.8% | 15.8% |
| Single householder, no children | 5.7% | 14.7% | 10.8% |