| | Bay City, MI | Oil City, PA | United States |
| Population | 32,824 | 9,685 | 329,725,481 |
| Female Population | 52.3% | 49.4% | 50.5% |
| Male Population | 47.7% | 50.6% | 49.5% |
| Median Age | 39 | 41.3 | 38.4 |
| space3 | | | |
| Population - 2010 | 34,879 | 10,540 | 309,327,143 |
| Population - 2000 | 36,817 | 11,504 | 285,036,114 |
| Population - 1990 | 38,936 | 11,949 | 251,960,433 |
| Pop. 2000 to Now | -11.9% | -17.1% | 15.6% |
| Pop. 1990 to Now | -16.7% | -20.1% | 30.8% |
| space4 | | | |
| Population Density | 3,228.8 | 2,155.6 | 93.4 |
| Land Area | 10.2 | 4.5 | 3,531,905.4 |
| Water Area | 1.0 | 0.3 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Bay City, MI | Oil City, PA | United States |
| Age 0 to 4 | 4.8% | 4.3% | 5.9% |
| Age 5 to 9 | 6.1% | 6.3% | 6.1% |
| Age 10 to 14 | 6.4% | 6.1% | 6.6% |
| Age 15 to 17 | 4.3% | 5.5% | 3.9% |
| Age 18 to 20 | 3.8% | 3.4% | 4.0% |
| Age 21 to 24 | 5.6% | 4.5% | 5.2% |
| Age 25 to 34 | 13.5% | 11.8% | 13.8% |
| Age 35 to 44 | 13.4% | 12.6% | 12.9% |
| Age 45 to 54 | 13.0% | 13.7% | 12.6% |
| Age 55 to 59 | 6.9% | 4.8% | 6.7% |
| Age 60 to 64 | 7.7% | 8.7% | 6.3% |
| Age 65 to 74 | 8.7% | 11.0% | 9.6% |
| Age 75 to 84 | 3.8% | 5.4% | 4.5% |
| Age 85 and over | 2.0% | 1.9% | 1.9% |
| space1 | | | |
| Race | | | |
| | Bay City, MI | Oil City, PA | United States |
| White | 83.6% | 94.2% | 59.4% |
| Black | 2.3% | 1.2% | 12.2% |
| Asian | 0.5% | 0.1% | 5.6% |
| Native American | 0.2% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.2% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 3.0% | 2.5% | 3.2% |
| Hispanic | 10.1% | 2.1% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Bay City, MI | Oil City, PA | United States |
| Married Population | 38.1% | 45.2% | 49.8% |
| Currently Married | 36.5% | 42.2% | 48.0% |
| Married but Separated | 1.6% | 3.0% | 1.8% |
| Single Population | 61.9% | 54.8% | 50.2% |
| Never Married | 38.2% | 30.9% | 33.8% |
| Divorced | 17.3% | 17.7% | 10.8% |
| Widowed | 6.4% | 6.2% | 5.6% |
| space5 | | | |
| Household Size | 2.25 | 2.34 | 2.60 |
| Households | 14,417 | 4,019 | 124,010,992 |
| Family Households | 7,576 | 2,285 | 80,755,759 |
| Married couple, w/children | 21.3% | 34.1% | 30.5% |
| Married couple, no children | 38.8% | 36.5% | 42.9% |
| Non Family Households | 6,841 | 1,734 | 43,255,233 |
| Single householder, w/children | 28.0% | 19.6% | 15.8% |
| Single householder, no children | 11.9% | 9.8% | 10.8% |