| | Shenandoah, IA | Atlantic, IA | United States |
| Population | 4,874 | 6,795 | 329,725,481 |
| Female Population | 49.9% | 51.6% | 50.5% |
| Male Population | 50.1% | 48.4% | 49.5% |
| Median Age | 41.9 | 43.9 | 38.4 |
| space3 | | | |
| Population - 2010 | 5,134 | 7,102 | 309,327,143 |
| Population - 2000 | 5,546 | 7,257 | 285,036,114 |
| Population - 1990 | 5,572 | 7,432 | 251,960,433 |
| Pop. 2000 to Now | -13.8% | -10.3% | 15.6% |
| Pop. 1990 to Now | -14.2% | -12.4% | 30.8% |
| space4 | | | |
| Population Density | 1,300.8 | 816.6 | 93.4 |
| Land Area | 3.7 | 8.3 | 3,531,905.4 |
| Water Area | 0.0 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Shenandoah, IA | Atlantic, IA | United States |
| Age 0 to 4 | 6.1% | 6.0% | 5.9% |
| Age 5 to 9 | 6.0% | 5.7% | 6.1% |
| Age 10 to 14 | 7.9% | 4.3% | 6.6% |
| Age 15 to 17 | 2.7% | 4.2% | 3.9% |
| Age 18 to 20 | 2.7% | 1.8% | 4.0% |
| Age 21 to 24 | 3.1% | 4.6% | 5.2% |
| Age 25 to 34 | 11.9% | 11.1% | 13.8% |
| Age 35 to 44 | 13.4% | 14.3% | 12.9% |
| Age 45 to 54 | 8.0% | 11.7% | 12.6% |
| Age 55 to 59 | 6.7% | 6.9% | 6.7% |
| Age 60 to 64 | 7.7% | 6.6% | 6.3% |
| Age 65 to 74 | 12.7% | 12.6% | 9.6% |
| Age 75 to 84 | 6.8% | 5.9% | 4.5% |
| Age 85 and over | 4.3% | 4.3% | 1.9% |
| space1 | | | |
| Race | | | |
| | Shenandoah, IA | Atlantic, IA | United States |
| White | 91.3% | 93.2% | 59.4% |
| Black | 0.8% | 1.4% | 12.2% |
| Asian | 0.1% | 0.6% | 5.6% |
| Native American | 0.0% | 0.2% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 0.0% | 0.0% | 0.4% |
| Two or More Races | 3.5% | 0.6% | 3.2% |
| Hispanic | 4.2% | 4.0% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Shenandoah, IA | Atlantic, IA | United States |
| Married Population | 50.5% | 50.1% | 49.8% |
| Currently Married | 48.9% | 48.9% | 48.0% |
| Married but Separated | 1.5% | 1.2% | 1.8% |
| Single Population | 49.5% | 49.9% | 50.2% |
| Never Married | 25.5% | 24.5% | 33.8% |
| Divorced | 15.1% | 17.3% | 10.8% |
| Widowed | 8.9% | 8.1% | 5.6% |
| space5 | | | |
| Household Size | 2.26 | 2.07 | 2.60 |
| Households | 2,112 | 3,202 | 124,010,992 |
| Family Households | 1,155 | 1,705 | 80,755,759 |
| Married couple, w/children | 31.1% | 28.9% | 30.5% |
| Married couple, no children | 49.1% | 45.9% | 42.9% |
| Non Family Households | 957 | 1,497 | 43,255,233 |
| Single householder, w/children | 18.5% | 16.8% | 15.8% |
| Single householder, no children | 1.3% | 8.3% | 10.8% |