| | Arcanum, OH | Waterloo, IA | United States |
| Population | 2,661 | 67,695 | 329,725,481 |
| Female Population | 50.4% | 50.2% | 50.5% |
| Male Population | 49.6% | 49.8% | 49.5% |
| Median Age | 36.3 | 36.8 | 38.4 |
| space3 | | | |
| Population - 2010 | 2,114 | 68,488 | 309,327,143 |
| Population - 2000 | 2,076 | 68,747 | 285,036,114 |
| Population - 1990 | 1,953 | 66,467 | 251,960,433 |
| Pop. 2000 to Now | -3.5% | -2.1% | 15.6% |
| Pop. 1990 to Now | 2.6% | 1.2% | 30.8% |
| space4 | | | |
| Population Density | 2,092.0 | 1,100.9 | 93.4 |
| Land Area | 1.3 | 61.5 | 3,531,905.4 |
| Water Area | 0.0 | 1.7 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Arcanum, OH | Waterloo, IA | United States |
| Age 0 to 4 | 6.3% | 7.1% | 5.9% |
| Age 5 to 9 | 7.7% | 6.6% | 6.1% |
| Age 10 to 14 | 7.7% | 6.2% | 6.6% |
| Age 15 to 17 | 4.1% | 4.0% | 3.9% |
| Age 18 to 20 | 5.2% | 3.4% | 4.0% |
| Age 21 to 24 | 3.3% | 5.8% | 5.2% |
| Age 25 to 34 | 13.9% | 14.3% | 13.8% |
| Age 35 to 44 | 13.6% | 12.4% | 12.9% |
| Age 45 to 54 | 10.9% | 11.3% | 12.6% |
| Age 55 to 59 | 6.2% | 6.0% | 6.7% |
| Age 60 to 64 | 3.8% | 6.8% | 6.3% |
| Age 65 to 74 | 8.8% | 9.8% | 9.6% |
| Age 75 to 84 | 6.7% | 4.4% | 4.5% |
| Age 85 and over | 1.8% | 2.1% | 1.9% |
| space1 | | | |
| Race | | | |
| | Arcanum, OH | Waterloo, IA | United States |
| White | 92.5% | 68.9% | 59.4% |
| Black | 2.3% | 17.1% | 12.2% |
| Asian | 0.0% | 2.5% | 5.6% |
| Native American | 0.0% | 0.2% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.4% | 0.2% |
| Other | 0.0% | 0.1% | 0.4% |
| Two or More Races | 3.6% | 3.7% | 3.2% |
| Hispanic | 1.7% | 7.1% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Arcanum, OH | Waterloo, IA | United States |
| Married Population | 58.5% | 45.5% | 49.8% |
| Currently Married | 56.9% | 43.8% | 48.0% |
| Married but Separated | 1.5% | 1.7% | 1.8% |
| Single Population | 41.5% | 54.5% | 50.2% |
| Never Married | 26.2% | 37.5% | 33.8% |
| Divorced | 9.6% | 11.6% | 10.8% |
| Widowed | 5.8% | 5.4% | 5.6% |
| space5 | | | |
| Household Size | 2.53 | 2.31 | 2.60 |
| Households | 1,053 | 28,912 | 124,010,992 |
| Family Households | 771 | 16,798 | 80,755,759 |
| Married couple, w/children | 27.8% | 26.4% | 30.5% |
| Married couple, no children | 47.6% | 41.6% | 42.9% |
| Non Family Households | 282 | 12,114 | 43,255,233 |
| Single householder, w/children | 16.1% | 22.6% | 15.8% |
| Single householder, no children | 8.6% | 9.4% | 10.8% |