| | Cudahy, CA | Downey, CA | United States |
| Population | 23,003 | 114,293 | 329,725,481 |
| Female Population | 51.5% | 51.6% | 50.5% |
| Male Population | 48.5% | 48.4% | 49.5% |
| Median Age | 30.1 | 35.9 | 38.4 |
| space3 | | | |
| Population - 2010 | 23,806 | 111,766 | 309,327,143 |
| Population - 2000 | 24,208 | 107,323 | 285,036,114 |
| Population - 1990 | 22,817 | 91,444 | 251,960,433 |
| Pop. 2000 to Now | -4.5% | 1.8% | 15.6% |
| Pop. 1990 to Now | 1.4% | 19.4% | 30.8% |
| space4 | | | |
| Population Density | 19,560.4 | 9,211.2 | 93.4 |
| Land Area | 1.2 | 12.4 | 3,531,905.4 |
| Water Area | 0.1 | 0.2 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Cudahy, CA | Downey, CA | United States |
| Age 0 to 4 | 6.6% | 5.6% | 5.9% |
| Age 5 to 9 | 7.2% | 6.5% | 6.1% |
| Age 10 to 14 | 10.3% | 7.1% | 6.6% |
| Age 15 to 17 | 5.7% | 4.3% | 3.9% |
| Age 18 to 20 | 5.3% | 3.8% | 4.0% |
| Age 21 to 24 | 6.7% | 5.4% | 5.2% |
| Age 25 to 34 | 15.3% | 15.8% | 13.8% |
| Age 35 to 44 | 13.7% | 13.0% | 12.9% |
| Age 45 to 54 | 12.3% | 13.6% | 12.6% |
| Age 55 to 59 | 5.5% | 5.8% | 6.7% |
| Age 60 to 64 | 3.5% | 5.7% | 6.3% |
| Age 65 to 74 | 5.2% | 8.4% | 9.6% |
| Age 75 to 84 | 1.7% | 3.2% | 4.5% |
| Age 85 and over | 1.0% | 1.8% | 1.9% |
| space1 | | | |
| Race | | | |
| | Cudahy, CA | Downey, CA | United States |
| White | 2.2% | 13.9% | 59.4% |
| Black | 0.7% | 3.5% | 12.2% |
| Asian | 0.2% | 6.5% | 5.6% |
| Native American | 0.1% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.2% | 0.2% |
| Other | 0.3% | 0.3% | 0.4% |
| Two or More Races | 0.0% | 1.4% | 3.2% |
| Hispanic | 96.5% | 74.2% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Cudahy, CA | Downey, CA | United States |
| Married Population | 39.7% | 46.3% | 49.8% |
| Currently Married | 37.1% | 44.2% | 48.0% |
| Married but Separated | 2.6% | 2.1% | 1.8% |
| Single Population | 60.3% | 53.7% | 50.2% |
| Never Married | 52.4% | 39.8% | 33.8% |
| Divorced | 5.0% | 9.3% | 10.8% |
| Widowed | 2.9% | 4.5% | 5.6% |
| space5 | | | |
| Household Size | 3.98 | 3.29 | 2.60 |
| Households | 5,775 | 34,497 | 124,010,992 |
| Family Households | 4,929 | 27,400 | 80,755,759 |
| Married couple, w/children | 28.4% | 31.7% | 30.5% |
| Married couple, no children | 25.6% | 32.0% | 42.9% |
| Non Family Households | 846 | 7,097 | 43,255,233 |
| Single householder, w/children | 29.5% | 20.3% | 15.8% |
| Single householder, no children | 16.5% | 16.0% | 10.8% |