| | Foothill Farms, CA | Rosemont, CA | United States |
| Population | 37,432 | 24,343 | 329,725,481 |
| Female Population | 49.9% | 52.6% | 50.5% |
| Male Population | 50.1% | 47.4% | 49.5% |
| Median Age | 33.1 | 34.8 | 38.4 |
| space3 | | | |
| Population - 2010 | 32,800 | 22,851 | 309,327,143 |
| Population - 2000 | 17,426 | 22,904 | 285,036,114 |
| Population - 1990 | 17,135 | 22,851 | 251,960,433 |
| Pop. 2000 to Now | 101.5% | 8.0% | 15.6% |
| Pop. 1990 to Now | 104.9% | 8.3% | 30.8% |
| space4 | | | |
| Population Density | 8,916.6 | 5,566.7 | 93.4 |
| Land Area | 4.2 | 4.4 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Foothill Farms, CA | Rosemont, CA | United States |
| Age 0 to 4 | 8.3% | 5.8% | 5.9% |
| Age 5 to 9 | 8.9% | 6.8% | 6.1% |
| Age 10 to 14 | 7.9% | 6.6% | 6.6% |
| Age 15 to 17 | 4.1% | 4.3% | 3.9% |
| Age 18 to 20 | 3.0% | 3.3% | 4.0% |
| Age 21 to 24 | 5.3% | 5.1% | 5.2% |
| Age 25 to 34 | 16.0% | 18.4% | 13.8% |
| Age 35 to 44 | 13.5% | 11.6% | 12.9% |
| Age 45 to 54 | 10.3% | 15.3% | 12.6% |
| Age 55 to 59 | 6.8% | 4.5% | 6.7% |
| Age 60 to 64 | 4.7% | 5.1% | 6.3% |
| Age 65 to 74 | 6.6% | 8.1% | 9.6% |
| Age 75 to 84 | 3.6% | 2.8% | 4.5% |
| Age 85 and over | 1.0% | 2.3% | 1.9% |
| space1 | | | |
| Race | | | |
| | Foothill Farms, CA | Rosemont, CA | United States |
| White | 51.0% | 44.0% | 59.4% |
| Black | 12.1% | 12.6% | 12.2% |
| Asian | 8.1% | 12.8% | 5.6% |
| Native American | 0.3% | 0.3% | 0.6% |
| Hawaiian, Pacific Islander | 0.1% | 0.2% | 0.2% |
| Other | 0.3% | 0.5% | 0.4% |
| Two or More Races | 5.0% | 7.5% | 3.2% |
| Hispanic | 23.0% | 22.1% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Foothill Farms, CA | Rosemont, CA | United States |
| Married Population | 43.3% | 42.5% | 49.8% |
| Currently Married | 41.0% | 41.0% | 48.0% |
| Married but Separated | 2.3% | 1.5% | 1.8% |
| Single Population | 56.7% | 57.5% | 50.2% |
| Never Married | 37.9% | 40.2% | 33.8% |
| Divorced | 14.0% | 12.7% | 10.8% |
| Widowed | 4.7% | 4.6% | 5.6% |
| space5 | | | |
| Household Size | 2.94 | 2.70 | 2.60 |
| Households | 12,698 | 8,921 | 124,010,992 |
| Family Households | 8,726 | 5,725 | 80,755,759 |
| Married couple, w/children | 28.8% | 30.8% | 30.5% |
| Married couple, no children | 28.6% | 32.3% | 42.9% |
| Non Family Households | 3,972 | 3,196 | 43,255,233 |
| Single householder, w/children | 28.1% | 21.0% | 15.8% |
| Single householder, no children | 14.6% | 15.9% | 10.8% |