| | Algona, IA | Mount Ayr, IA | United States |
| Population | 5,407 | 1,832 | 329,725,481 |
| Female Population | 53.2% | 52.0% | 50.5% |
| Male Population | 46.8% | 48.0% | 49.5% |
| Median Age | 46.6 | 44.1 | 38.4 |
| space3 | | | |
| Population - 2010 | 5,550 | 1,687 | 309,327,143 |
| Population - 2000 | 5,741 | 1,822 | 285,036,114 |
| Population - 1990 | 6,015 | 1,796 | 251,960,433 |
| Pop. 2000 to Now | -6.7% | -12.1% | 15.6% |
| Pop. 1990 to Now | -10.9% | -10.9% | 30.8% |
| space4 | | | |
| Population Density | 1,201.6 | 689.8 | 93.4 |
| Land Area | 4.5 | 2.7 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Algona, IA | Mount Ayr, IA | United States |
| Age 0 to 4 | 6.9% | 5.5% | 5.9% |
| Age 5 to 9 | 4.1% | 4.5% | 6.1% |
| Age 10 to 14 | 4.4% | 7.3% | 6.6% |
| Age 15 to 17 | 3.2% | 5.5% | 3.9% |
| Age 18 to 20 | 3.9% | 6.8% | 4.0% |
| Age 21 to 24 | 4.9% | 2.2% | 5.2% |
| Age 25 to 34 | 9.1% | 8.8% | 13.8% |
| Age 35 to 44 | 12.9% | 10.9% | 12.9% |
| Age 45 to 54 | 10.1% | 10.9% | 12.6% |
| Age 55 to 59 | 5.9% | 7.1% | 6.7% |
| Age 60 to 64 | 7.6% | 7.9% | 6.3% |
| Age 65 to 74 | 11.2% | 10.9% | 9.6% |
| Age 75 to 84 | 8.7% | 7.2% | 4.5% |
| Age 85 and over | 7.1% | 4.6% | 1.9% |
| space1 | | | |
| Race | | | |
| | Algona, IA | Mount Ayr, IA | United States |
| White | 91.5% | 93.5% | 59.4% |
| Black | 0.7% | 0.2% | 12.2% |
| Asian | 0.5% | 0.3% | 5.6% |
| Native American | 0.0% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 1.8% | 0.9% | 3.2% |
| Hispanic | 5.5% | 5.1% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Algona, IA | Mount Ayr, IA | United States |
| Married Population | 46.8% | 49.0% | 49.8% |
| Currently Married | 46.1% | 48.8% | 48.0% |
| Married but Separated | 0.7% | 0.3% | 1.8% |
| Single Population | 53.2% | 51.0% | 50.2% |
| Never Married | 28.8% | 26.6% | 33.8% |
| Divorced | 11.9% | 14.7% | 10.8% |
| Widowed | 12.5% | 9.7% | 5.6% |
| space5 | | | |
| Household Size | 2.04 | 2.29 | 2.60 |
| Households | 2,575 | 767 | 124,010,992 |
| Family Households | 1,301 | 467 | 80,755,759 |
| Married couple, w/children | 25.2% | 23.8% | 30.5% |
| Married couple, no children | 51.3% | 50.3% | 42.9% |
| Non Family Households | 1,274 | 300 | 43,255,233 |
| Single householder, w/children | 20.6% | 15.0% | 15.8% |
| Single householder, no children | 2.9% | 10.9% | 10.8% |