| | Saginaw, MI | Boston, MA | United States |
| Population | 44,796 | 672,814 | 329,725,481 |
| Female Population | 50.6% | 52.0% | 50.5% |
| Male Population | 49.4% | 48.0% | 49.5% |
| Median Age | 36.1 | 32.6 | 38.4 |
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| Population - 2010 | 51,390 | 621,053 | 309,327,143 |
| Population - 2000 | 61,799 | 589,141 | 285,036,114 |
| Population - 1990 | 69,512 | 574,283 | 251,960,433 |
| Pop. 2000 to Now | -22.6% | 17.4% | 15.6% |
| Pop. 1990 to Now | -31.2% | 20.4% | 30.8% |
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| Population Density | 2,622.4 | 13,919.5 | 93.4 |
| Land Area | 17.1 | 48.3 | 3,531,905.4 |
| Water Area | 0.7 | 41.3 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Saginaw, MI | Boston, MA | United States |
| Age 0 to 4 | 8.0% | 4.8% | 5.9% |
| Age 5 to 9 | 7.1% | 4.1% | 6.1% |
| Age 10 to 14 | 7.5% | 4.4% | 6.6% |
| Age 15 to 17 | 4.2% | 2.5% | 3.9% |
| Age 18 to 20 | 3.5% | 7.0% | 4.0% |
| Age 21 to 24 | 5.1% | 7.9% | 5.2% |
| Age 25 to 34 | 13.4% | 23.9% | 13.8% |
| Age 35 to 44 | 13.3% | 12.8% | 12.9% |
| Age 45 to 54 | 11.5% | 10.6% | 12.6% |
| Age 55 to 59 | 6.2% | 5.4% | 6.7% |
| Age 60 to 64 | 6.4% | 4.9% | 6.3% |
| Age 65 to 74 | 8.4% | 7.0% | 9.6% |
| Age 75 to 84 | 3.3% | 3.2% | 4.5% |
| Age 85 and over | 2.1% | 1.6% | 1.9% |
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| Race | | | |
| | Saginaw, MI | Boston, MA | United States |
| White | 35.9% | 44.0% | 59.4% |
| Black | 44.2% | 21.7% | 12.2% |
| Asian | 0.2% | 9.6% | 5.6% |
| Native American | 0.1% | 0.2% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.8% | 0.4% |
| Two or More Races | 4.0% | 3.9% | 3.2% |
| Hispanic | 15.7% | 19.8% | 18.4% |
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| Marriage & Family | | | |
| | Saginaw, MI | Boston, MA | United States |
| Married Population | 30.2% | 33.4% | 49.8% |
| Currently Married | 27.8% | 30.9% | 48.0% |
| Married but Separated | 2.4% | 2.5% | 1.8% |
| Single Population | 69.8% | 66.6% | 50.2% |
| Never Married | 48.4% | 55.7% | 33.8% |
| Divorced | 15.3% | 7.3% | 10.8% |
| Widowed | 6.1% | 3.6% | 5.6% |
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| Household Size | 2.40 | 2.30 | 2.60 |
| Households | 18,092 | 271,950 | 124,010,992 |
| Family Households | 9,736 | 128,147 | 80,755,759 |
| Married couple, w/children | 18.5% | 22.5% | 30.5% |
| Married couple, no children | 26.6% | 37.9% | 42.9% |
| Non Family Households | 8,356 | 143,803 | 43,255,233 |
| Single householder, w/children | 35.4% | 21.5% | 15.8% |
| Single householder, no children | 19.4% | 18.1% | 10.8% |