| | Bay St. Louis, MS | Iuka, MS | United States |
| Population | 9,568 | 3,084 | 329,725,481 |
| Female Population | 53.2% | 54.7% | 50.5% |
| Male Population | 46.8% | 45.3% | 49.5% |
| Median Age | 48.3 | 40.3 | 38.4 |
| space3 | | | |
| Population - 2010 | 9,324 | 3,036 | 309,327,143 |
| Population - 2000 | 8,209 | 3,059 | 285,036,114 |
| Population - 1990 | 8,063 | 3,122 | 251,960,433 |
| Pop. 2000 to Now | 77.0% | -4.3% | 15.6% |
| Pop. 1990 to Now | 80.2% | -6.2% | 30.8% |
| space4 | | | |
| Population Density | 651.2 | 318.1 | 93.4 |
| Land Area | 14.7 | 9.7 | 3,531,905.4 |
| Water Area | 11.9 | 0.0 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Bay St. Louis, MS | Iuka, MS | United States |
| Age 0 to 4 | 4.6% | 9.2% | 5.9% |
| Age 5 to 9 | 3.3% | 4.1% | 6.1% |
| Age 10 to 14 | 6.1% | 5.8% | 6.6% |
| Age 15 to 17 | 2.9% | 2.7% | 3.9% |
| Age 18 to 20 | 3.8% | 3.9% | 4.0% |
| Age 21 to 24 | 3.7% | 3.7% | 5.2% |
| Age 25 to 34 | 12.1% | 13.4% | 13.8% |
| Age 35 to 44 | 9.3% | 12.5% | 12.9% |
| Age 45 to 54 | 16.7% | 11.0% | 12.6% |
| Age 55 to 59 | 6.8% | 7.7% | 6.7% |
| Age 60 to 64 | 8.5% | 4.1% | 6.3% |
| Age 65 to 74 | 15.2% | 8.9% | 9.6% |
| Age 75 to 84 | 5.3% | 9.5% | 4.5% |
| Age 85 and over | 1.6% | 3.5% | 1.9% |
| space1 | | | |
| Race | | | |
| | Bay St. Louis, MS | Iuka, MS | United States |
| White | 70.5% | 93.6% | 59.4% |
| Black | 18.4% | 4.9% | 12.2% |
| Asian | 1.1% | 0.0% | 5.6% |
| Native American | 0.3% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.0% | 0.2% |
| Other | 3.4% | 0.0% | 0.4% |
| Two or More Races | 0.4% | 1.4% | 3.2% |
| Hispanic | 6.0% | 0.1% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Bay St. Louis, MS | Iuka, MS | United States |
| Married Population | 52.7% | 51.5% | 49.8% |
| Currently Married | 49.4% | 48.9% | 48.0% |
| Married but Separated | 3.2% | 2.7% | 1.8% |
| Single Population | 47.3% | 48.5% | 50.2% |
| Never Married | 26.8% | 25.1% | 33.8% |
| Divorced | 14.9% | 12.3% | 10.8% |
| Widowed | 5.6% | 11.0% | 5.6% |
| space5 | | | |
| Household Size | 2.20 | 2.28 | 2.60 |
| Households | 4,273 | 1,256 | 124,010,992 |
| Family Households | 2,809 | 814 | 80,755,759 |
| Married couple, w/children | 16.2% | 28.5% | 30.5% |
| Married couple, no children | 49.2% | 38.2% | 42.9% |
| Non Family Households | 1,464 | 442 | 43,255,233 |
| Single householder, w/children | 28.0% | 25.7% | 15.8% |
| Single householder, no children | 6.6% | 7.6% | 10.8% |