| | Willowbrook, CA | Elkhart, IN | United States |
| Population | 24,006 | 53,838 | 329,725,481 |
| Female Population | 51.7% | 51.7% | 50.5% |
| Male Population | 48.3% | 48.3% | 49.5% |
| Median Age | 28.7 | 34 | 38.4 |
| space3 | | | |
| Population - 2010 | 35,174 | 51,844 | 309,327,143 |
| Population - 2000 | 34,138 | 51,874 | 285,036,114 |
| Population - 1990 | 32,772 | 43,627 | 251,960,433 |
| Pop. 2000 to Now | -34.5% | 0.6% | 15.6% |
| Pop. 1990 to Now | -31.8% | 19.6% | 30.8% |
| space4 | | | |
| Population Density | 15,517.8 | 1,986.0 | 93.4 |
| Land Area | 1.5 | 27.1 | 3,531,905.4 |
| Water Area | 0.0 | 1.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Willowbrook, CA | Elkhart, IN | United States |
| Age 0 to 4 | 9.4% | 8.6% | 5.9% |
| Age 5 to 9 | 8.8% | 7.2% | 6.1% |
| Age 10 to 14 | 8.9% | 7.6% | 6.6% |
| Age 15 to 17 | 4.4% | 3.4% | 3.9% |
| Age 18 to 20 | 3.7% | 4.1% | 4.0% |
| Age 21 to 24 | 6.9% | 5.3% | 5.2% |
| Age 25 to 34 | 18.9% | 14.9% | 13.8% |
| Age 35 to 44 | 11.1% | 11.3% | 12.9% |
| Age 45 to 54 | 10.8% | 13.0% | 12.6% |
| Age 55 to 59 | 5.7% | 5.7% | 6.7% |
| Age 60 to 64 | 4.8% | 5.4% | 6.3% |
| Age 65 to 74 | 3.5% | 7.4% | 9.6% |
| Age 75 to 84 | 2.4% | 3.4% | 4.5% |
| Age 85 and over | 0.8% | 2.8% | 1.9% |
| space1 | | | |
| Race | | | |
| | Willowbrook, CA | Elkhart, IN | United States |
| White | 0.5% | 56.8% | 59.4% |
| Black | 16.4% | 13.3% | 12.2% |
| Asian | 0.8% | 0.6% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.1% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 0.6% | 3.1% | 3.2% |
| Hispanic | 81.7% | 26.0% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Willowbrook, CA | Elkhart, IN | United States |
| Married Population | 39.2% | 37.9% | 49.8% |
| Currently Married | 36.2% | 35.6% | 48.0% |
| Married but Separated | 3.1% | 2.3% | 1.8% |
| Single Population | 60.8% | 62.1% | 50.2% |
| Never Married | 50.3% | 38.3% | 33.8% |
| Divorced | 6.1% | 16.3% | 10.8% |
| Widowed | 4.4% | 7.5% | 5.6% |
| space5 | | | |
| Household Size | 4.12 | 2.50 | 2.60 |
| Households | 5,789 | 21,212 | 124,010,992 |
| Family Households | 4,646 | 12,542 | 80,755,759 |
| Married couple, w/children | 30.6% | 21.7% | 30.5% |
| Married couple, no children | 20.2% | 31.9% | 42.9% |
| Non Family Households | 1,143 | 8,670 | 43,255,233 |
| Single householder, w/children | 36.0% | 31.0% | 15.8% |
| Single householder, no children | 13.2% | 15.4% | 10.8% |