| | Ridgefield, NJ | Leonia, NJ | United States |
| Population | 11,477 | 9,283 | 329,725,481 |
| Female Population | 50.4% | 51.2% | 50.5% |
| Male Population | 49.7% | 48.8% | 49.5% |
| Median Age | 41.8 | 46.1 | 38.4 |
| space3 | | | |
| Population - 2010 | 11,071 | 8,954 | 309,327,143 |
| Population - 2000 | 10,830 | 8,914 | 285,036,114 |
| Population - 1990 | 9,996 | 8,365 | 251,960,433 |
| Pop. 2000 to Now | 2.7% | 0.8% | 15.6% |
| Pop. 1990 to Now | 11.3% | 7.5% | 30.8% |
| space4 | | | |
| Population Density | 4,513.2 | 6,095.2 | 93.4 |
| Land Area | 2.5 | 1.5 | 3,531,905.4 |
| Water Area | 0.3 | 0.1 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Ridgefield, NJ | Leonia, NJ | United States |
| Age 0 to 4 | 2.5% | 6.0% | 5.9% |
| Age 5 to 9 | 3.0% | 5.0% | 6.1% |
| Age 10 to 14 | 7.2% | 6.2% | 6.6% |
| Age 15 to 17 | 6.0% | 4.3% | 3.9% |
| Age 18 to 20 | 4.1% | 2.5% | 4.0% |
| Age 21 to 24 | 3.9% | 3.8% | 5.2% |
| Age 25 to 34 | 13.7% | 9.2% | 13.8% |
| Age 35 to 44 | 12.9% | 11.9% | 12.9% |
| Age 45 to 54 | 13.7% | 14.8% | 12.6% |
| Age 55 to 59 | 9.7% | 8.2% | 6.7% |
| Age 60 to 64 | 8.1% | 10.0% | 6.3% |
| Age 65 to 74 | 9.7% | 10.1% | 9.6% |
| Age 75 to 84 | 3.1% | 6.2% | 4.5% |
| Age 85 and over | 2.5% | 1.8% | 1.9% |
| space1 | | | |
| Race | | | |
| | Ridgefield, NJ | Leonia, NJ | United States |
| White | 35.2% | 32.0% | 59.4% |
| Black | 0.1% | 2.8% | 12.2% |
| Asian | 28.8% | 38.5% | 5.6% |
| Native American | 0.0% | 0.1% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.3% | 0.2% |
| Other | 0.1% | 0.7% | 0.4% |
| Two or More Races | 0.5% | 2.4% | 3.2% |
| Hispanic | 35.2% | 23.2% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Ridgefield, NJ | Leonia, NJ | United States |
| Married Population | 54.9% | 63.9% | 49.8% |
| Currently Married | 52.0% | 62.7% | 48.0% |
| Married but Separated | 2.9% | 1.3% | 1.8% |
| Single Population | 45.1% | 36.1% | 50.2% |
| Never Married | 32.0% | 23.2% | 33.8% |
| Divorced | 8.7% | 7.0% | 10.8% |
| Widowed | 4.4% | 5.9% | 5.6% |
| space5 | | | |
| Household Size | 2.84 | 2.67 | 2.60 |
| Households | 4,032 | 3,470 | 124,010,992 |
| Family Households | 3,100 | 2,468 | 80,755,759 |
| Married couple, w/children | 34.4% | 37.6% | 30.5% |
| Married couple, no children | 38.1% | 48.3% | 42.9% |
| Non Family Households | 932 | 1,002 | 43,255,233 |
| Single householder, w/children | 9.6% | 6.5% | 15.8% |
| Single householder, no children | 17.9% | 7.6% | 10.8% |