| | Dunkirk, IN | Hartford City, IN | United States |
| Population | 1,783 | 5,895 | 329,725,481 |
| Female Population | 58.7% | 53.5% | 50.5% |
| Male Population | 41.3% | 46.5% | 49.5% |
| Median Age | 44.9 | 39.4 | 38.4 |
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| Population - 2010 | 2,358 | 6,166 | 309,327,143 |
| Population - 2000 | 2,646 | 6,928 | 285,036,114 |
| Population - 1990 | 2,739 | 6,960 | 251,960,433 |
| Pop. 2000 to Now | -15.0% | -18.2% | 15.6% |
| Pop. 1990 to Now | -17.9% | -18.6% | 30.8% |
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| Population Density | 1,418.5 | 1,518.6 | 93.4 |
| Land Area | 1.3 | 3.9 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
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| Est. Total Population By Age | | | |
| | Dunkirk, IN | Hartford City, IN | United States |
| Age 0 to 4 | 6.9% | 5.5% | 5.9% |
| Age 5 to 9 | 4.7% | 8.4% | 6.1% |
| Age 10 to 14 | 4.8% | 7.5% | 6.6% |
| Age 15 to 17 | 6.0% | 4.0% | 3.9% |
| Age 18 to 20 | 3.0% | 4.8% | 4.0% |
| Age 21 to 24 | 7.5% | 3.5% | 5.2% |
| Age 25 to 34 | 6.5% | 12.9% | 13.8% |
| Age 35 to 44 | 11.1% | 9.1% | 12.9% |
| Age 45 to 54 | 16.6% | 11.6% | 12.6% |
| Age 55 to 59 | 5.8% | 7.2% | 6.7% |
| Age 60 to 64 | 7.3% | 6.0% | 6.3% |
| Age 65 to 74 | 12.3% | 10.6% | 9.6% |
| Age 75 to 84 | 6.7% | 6.4% | 4.5% |
| Age 85 and over | 0.8% | 2.4% | 1.9% |
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| Race | | | |
| | Dunkirk, IN | Hartford City, IN | United States |
| White | 95.2% | 95.1% | 59.4% |
| Black | 1.2% | 0.6% | 12.2% |
| Asian | 0.0% | 0.0% | 5.6% |
| Native American | 0.0% | 0.5% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 1.3% | 1.4% | 3.2% |
| Hispanic | 2.3% | 2.3% | 18.4% |
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| Marriage & Family | | | |
| | Dunkirk, IN | Hartford City, IN | United States |
| Married Population | 45.3% | 49.1% | 49.8% |
| Currently Married | 43.3% | 47.2% | 48.0% |
| Married but Separated | 1.9% | 1.9% | 1.8% |
| Single Population | 54.7% | 50.9% | 50.2% |
| Never Married | 30.8% | 28.7% | 33.8% |
| Divorced | 18.2% | 14.0% | 10.8% |
| Widowed | 5.7% | 8.2% | 5.6% |
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| Household Size | 2.29 | 2.24 | 2.60 |
| Households | 780 | 2,619 | 124,010,992 |
| Family Households | 487 | 1,498 | 80,755,759 |
| Married couple, w/children | 21.4% | 29.0% | 30.5% |
| Married couple, no children | 42.3% | 45.1% | 42.9% |
| Non Family Households | 293 | 1,121 | 43,255,233 |
| Single householder, w/children | 27.9% | 21.0% | 15.8% |
| Single householder, no children | 8.4% | 4.9% | 10.8% |