| | Prairie du Chien, WI | Marquette, IA | United States |
| Population | 5,549 | 462 | 329,725,481 |
| Female Population | 45.1% | 52.2% | 50.5% |
| Male Population | 54.9% | 47.8% | 49.5% |
| Median Age | 46.7 | 45.8 | 38.4 |
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| Population - 2010 | 5,890 | 464 | 309,327,143 |
| Population - 2000 | 6,018 | 421 | 285,036,114 |
| Population - 1990 | 5,659 | 479 | 251,960,433 |
| Pop. 2000 to Now | -8.1% | 6.4% | 15.6% |
| Pop. 1990 to Now | -2.3% | -6.5% | 30.8% |
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| Population Density | 949.5 | 246.8 | 93.4 |
| Land Area | 5.8 | 1.9 | 3,531,905.4 |
| Water Area | 0.8 | 0.1 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Prairie du Chien, WI | Marquette, IA | United States |
| Age 0 to 4 | 4.9% | 3.9% | 5.9% |
| Age 5 to 9 | 5.0% | 2.8% | 6.1% |
| Age 10 to 14 | 5.4% | 4.5% | 6.6% |
| Age 15 to 17 | 2.3% | 4.8% | 3.9% |
| Age 18 to 20 | 3.0% | 3.5% | 4.0% |
| Age 21 to 24 | 4.0% | 7.4% | 5.2% |
| Age 25 to 34 | 13.3% | 11.5% | 13.8% |
| Age 35 to 44 | 11.0% | 9.5% | 12.9% |
| Age 45 to 54 | 11.9% | 14.3% | 12.6% |
| Age 55 to 59 | 9.2% | 13.9% | 6.7% |
| Age 60 to 64 | 7.6% | 3.7% | 6.3% |
| Age 65 to 74 | 11.5% | 10.6% | 9.6% |
| Age 75 to 84 | 6.7% | 7.6% | 4.5% |
| Age 85 and over | 4.2% | 2.2% | 1.9% |
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| Race | | | |
| | Prairie du Chien, WI | Marquette, IA | United States |
| White | 90.2% | 93.7% | 59.4% |
| Black | 4.4% | 0.0% | 12.2% |
| Asian | 0.0% | 0.4% | 5.6% |
| Native American | 0.0% | 0.6% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 2.4% | 1.7% | 3.2% |
| Hispanic | 2.9% | 3.5% | 18.4% |
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| Marriage & Family | | | |
| | Prairie du Chien, WI | Marquette, IA | United States |
| Married Population | 43.7% | 35.4% | 49.8% |
| Currently Married | 41.6% | 35.4% | 48.0% |
| Married but Separated | 2.0% | 0.0% | 1.8% |
| Single Population | 56.3% | 64.6% | 50.2% |
| Never Married | 35.4% | 39.8% | 33.8% |
| Divorced | 14.0% | 16.1% | 10.8% |
| Widowed | 7.0% | 8.8% | 5.6% |
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| Household Size | 2.17 | 1.80 | 2.60 |
| Households | 2,232 | 257 | 124,010,992 |
| Family Households | 1,252 | 111 | 80,755,759 |
| Married couple, w/children | 18.6% | 22.5% | 30.5% |
| Married couple, no children | 54.5% | 44.1% | 42.9% |
| Non Family Households | 980 | 146 | 43,255,233 |
| Single householder, w/children | 17.3% | 27.0% | 15.8% |
| Single householder, no children | 9.7% | 6.3% | 10.8% |