| | Warren, MI | Niagara Falls, NY | United States |
| Population | 138,996 | 48,763 | 329,725,481 |
| Female Population | 51.1% | 51.6% | 50.5% |
| Male Population | 48.9% | 48.4% | 49.5% |
| Median Age | 39.1 | 40.1 | 38.4 |
| space3 | | | |
| Population - 2010 | 134,083 | 49,996 | 309,327,143 |
| Population - 2000 | 138,247 | 55,593 | 285,036,114 |
| Population - 1990 | 144,864 | 61,840 | 251,960,433 |
| Pop. 2000 to Now | -3.9% | -14.8% | 15.6% |
| Pop. 1990 to Now | -8.3% | -23.4% | 30.8% |
| space4 | | | |
| Population Density | 4,045.3 | 3,461.8 | 93.4 |
| Land Area | 34.4 | 14.1 | 3,531,905.4 |
| Water Area | 0.1 | 2.7 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Warren, MI | Niagara Falls, NY | United States |
| Age 0 to 4 | 5.9% | 6.5% | 5.9% |
| Age 5 to 9 | 5.9% | 6.0% | 6.1% |
| Age 10 to 14 | 5.9% | 6.0% | 6.6% |
| Age 15 to 17 | 3.7% | 3.3% | 3.9% |
| Age 18 to 20 | 3.2% | 3.1% | 4.0% |
| Age 21 to 24 | 4.8% | 4.9% | 5.2% |
| Age 25 to 34 | 15.4% | 12.9% | 13.8% |
| Age 35 to 44 | 12.5% | 12.2% | 12.9% |
| Age 45 to 54 | 12.8% | 12.2% | 12.6% |
| Age 55 to 59 | 7.2% | 7.5% | 6.7% |
| Age 60 to 64 | 6.7% | 8.0% | 6.3% |
| Age 65 to 74 | 8.9% | 10.4% | 9.6% |
| Age 75 to 84 | 4.6% | 4.2% | 4.5% |
| Age 85 and over | 2.3% | 2.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Warren, MI | Niagara Falls, NY | United States |
| White | 62.6% | 65.3% | 59.4% |
| Black | 20.7% | 19.7% | 12.2% |
| Asian | 10.5% | 1.7% | 5.6% |
| Native American | 0.2% | 0.8% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.2% | 0.4% | 0.4% |
| Two or More Races | 3.3% | 5.5% | 3.2% |
| Hispanic | 2.6% | 6.5% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Warren, MI | Niagara Falls, NY | United States |
| Married Population | 43.7% | 38.4% | 49.8% |
| Currently Married | 41.8% | 35.9% | 48.0% |
| Married but Separated | 1.8% | 2.5% | 1.8% |
| Single Population | 56.3% | 61.6% | 50.2% |
| Never Married | 37.8% | 41.4% | 33.8% |
| Divorced | 11.8% | 13.0% | 10.8% |
| Widowed | 6.7% | 7.3% | 5.6% |
| space5 | | | |
| Household Size | 2.53 | 2.19 | 2.60 |
| Households | 54,502 | 22,130 | 124,010,992 |
| Family Households | 33,896 | 11,657 | 80,755,759 |
| Married couple, w/children | 26.0% | 18.1% | 30.5% |
| Married couple, no children | 38.5% | 38.4% | 42.9% |
| Non Family Households | 20,606 | 10,473 | 43,255,233 |
| Single householder, w/children | 17.9% | 29.0% | 15.8% |
| Single householder, no children | 17.6% | 14.5% | 10.8% |