| | Prairie City, IA | Sully, IA | United States |
| Population | 1,824 | 995 | 329,725,481 |
| Female Population | 55.1% | 45.0% | 50.5% |
| Male Population | 44.9% | 55.0% | 49.5% |
| Median Age | 36.3 | 44 | 38.4 |
| space3 | | | |
| Population - 2010 | 1,678 | 820 | 309,327,143 |
| Population - 2000 | 1,365 | 904 | 285,036,114 |
| Population - 1990 | 1,360 | 841 | 251,960,433 |
| Pop. 2000 to Now | 26.1% | -8.6% | 15.6% |
| Pop. 1990 to Now | 26.5% | -1.8% | 30.8% |
| space4 | | | |
| Population Density | 1,472.2 | 1,700.9 | 93.4 |
| Land Area | 1.2 | 0.6 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Prairie City, IA | Sully, IA | United States |
| Age 0 to 4 | 6.8% | 6.5% | 5.9% |
| Age 5 to 9 | 6.6% | 6.8% | 6.1% |
| Age 10 to 14 | 12.2% | 5.4% | 6.6% |
| Age 15 to 17 | 5.3% | 2.8% | 3.9% |
| Age 18 to 20 | 2.1% | 4.0% | 4.0% |
| Age 21 to 24 | 2.7% | 2.5% | 5.2% |
| Age 25 to 34 | 12.4% | 13.0% | 13.8% |
| Age 35 to 44 | 17.8% | 10.2% | 12.9% |
| Age 45 to 54 | 13.0% | 7.2% | 12.6% |
| Age 55 to 59 | 6.6% | 9.2% | 6.7% |
| Age 60 to 64 | 2.8% | 9.6% | 6.3% |
| Age 65 to 74 | 8.1% | 15.0% | 9.6% |
| Age 75 to 84 | 2.5% | 5.3% | 4.5% |
| Age 85 and over | 0.9% | 2.3% | 1.9% |
| space1 | | | |
| Race | | | |
| | Prairie City, IA | Sully, IA | United States |
| White | 98.0% | 96.6% | 59.4% |
| Black | 0.1% | 0.0% | 12.2% |
| Asian | 0.0% | 0.3% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.3% | 0.4% |
| Two or More Races | 0.7% | 2.6% | 3.2% |
| Hispanic | 1.3% | 0.2% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Prairie City, IA | Sully, IA | United States |
| Married Population | 61.4% | 62.3% | 49.8% |
| Currently Married | 61.2% | 61.9% | 48.0% |
| Married but Separated | 0.2% | 0.4% | 1.8% |
| Single Population | 38.6% | 37.7% | 50.2% |
| Never Married | 21.7% | 20.5% | 33.8% |
| Divorced | 12.8% | 12.4% | 10.8% |
| Widowed | 4.1% | 4.8% | 5.6% |
| space5 | | | |
| Household Size | 2.70 | 2.51 | 2.60 |
| Households | 667 | 397 | 124,010,992 |
| Family Households | 527 | 263 | 80,755,759 |
| Married couple, w/children | 37.8% | 33.1% | 30.5% |
| Married couple, no children | 39.8% | 60.1% | 42.9% |
| Non Family Households | 140 | 134 | 43,255,233 |
| Single householder, w/children | 18.8% | 6.1% | 15.8% |
| Single householder, no children | 3.6% | 0.8% | 10.8% |