| | Ishpeming, MI | Republic, MI | United States |
| Population | 6,223 | 591 | 329,725,481 |
| Female Population | 53.8% | 49.8% | 50.5% |
| Male Population | 46.2% | 50.3% | 49.5% |
| Median Age | 38.8 | 53.7 | 38.4 |
| space3 | | | |
| Population - 2010 | 6,476 | 564 | 309,327,143 |
| Population - 2000 | 6,686 | 614 | 285,036,114 |
| Population - 1990 | 7,200 | 637 | 251,960,433 |
| Pop. 2000 to Now | -4.6% | -34.7% | 15.6% |
| Pop. 1990 to Now | -11.4% | -37.1% | 30.8% |
| space4 | | | |
| Population Density | 711.4 | 163.4 | 93.4 |
| Land Area | 8.7 | 3.6 | 3,531,905.4 |
| Water Area | 0.6 | 0.3 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Ishpeming, MI | Republic, MI | United States |
| Age 0 to 4 | 7.1% | 3.9% | 5.9% |
| Age 5 to 9 | 4.2% | 3.2% | 6.1% |
| Age 10 to 14 | 7.7% | 6.6% | 6.6% |
| Age 15 to 17 | 4.3% | 3.7% | 3.9% |
| Age 18 to 20 | 5.8% | 6.3% | 4.0% |
| Age 21 to 24 | 5.9% | 3.7% | 5.2% |
| Age 25 to 34 | 11.1% | 3.9% | 13.8% |
| Age 35 to 44 | 9.6% | 11.3% | 12.9% |
| Age 45 to 54 | 16.6% | 8.5% | 12.6% |
| Age 55 to 59 | 4.8% | 9.3% | 6.7% |
| Age 60 to 64 | 4.7% | 17.6% | 6.3% |
| Age 65 to 74 | 10.1% | 12.0% | 9.6% |
| Age 75 to 84 | 5.4% | 7.6% | 4.5% |
| Age 85 and over | 2.6% | 2.4% | 1.9% |
| space1 | | | |
| Race | | | |
| | Ishpeming, MI | Republic, MI | United States |
| White | 92.4% | 98.5% | 59.4% |
| Black | 1.2% | 0.0% | 12.2% |
| Asian | 1.0% | 0.0% | 5.6% |
| Native American | 0.5% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.5% | 0.4% |
| Two or More Races | 3.7% | 0.5% | 3.2% |
| Hispanic | 1.2% | 0.5% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Ishpeming, MI | Republic, MI | United States |
| Married Population | 45.7% | 47.5% | 49.8% |
| Currently Married | 44.4% | 47.5% | 48.0% |
| Married but Separated | 1.3% | 0.0% | 1.8% |
| Single Population | 54.3% | 52.5% | 50.2% |
| Never Married | 33.1% | 28.8% | 33.8% |
| Divorced | 14.5% | 11.0% | 10.8% |
| Widowed | 6.6% | 12.7% | 5.6% |
| space5 | | | |
| Household Size | 2.46 | 2.15 | 2.60 |
| Households | 2,479 | 275 | 124,010,992 |
| Family Households | 1,459 | 164 | 80,755,759 |
| Married couple, w/children | 31.3% | 18.3% | 30.5% |
| Married couple, no children | 41.0% | 50.0% | 42.9% |
| Non Family Households | 1,020 | 111 | 43,255,233 |
| Single householder, w/children | 20.2% | 12.8% | 15.8% |
| Single householder, no children | 7.6% | 18.9% | 10.8% |