| | St. Marys, GA | Hilliard, OH | United States |
| Population | 18,200 | 35,530 | 329,725,481 |
| Female Population | 49.9% | 51.1% | 50.5% |
| Male Population | 50.1% | 48.9% | 49.5% |
| Median Age | 35 | 36.3 | 38.4 |
| space3 | | | |
| Population - 2010 | 17,267 | 28,331 | 309,327,143 |
| Population - 2000 | 13,761 | 24,230 | 285,036,114 |
| Population - 1990 | 8,187 | 11,796 | 251,960,433 |
| Pop. 2000 to Now | 37.0% | 51.9% | 15.6% |
| Pop. 1990 to Now | 130.3% | 211.9% | 30.8% |
| space4 | | | |
| Population Density | 797.5 | 2,490.4 | 93.4 |
| Land Area | 22.8 | 14.3 | 3,531,905.4 |
| Water Area | 2.2 | 0.2 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | St. Marys, GA | Hilliard, OH | United States |
| Age 0 to 4 | 7.5% | 5.8% | 5.9% |
| Age 5 to 9 | 5.8% | 6.8% | 6.1% |
| Age 10 to 14 | 7.4% | 8.2% | 6.6% |
| Age 15 to 17 | 5.0% | 5.3% | 3.9% |
| Age 18 to 20 | 4.8% | 2.3% | 4.0% |
| Age 21 to 24 | 5.0% | 4.5% | 5.2% |
| Age 25 to 34 | 14.5% | 15.0% | 13.8% |
| Age 35 to 44 | 12.4% | 14.8% | 12.9% |
| Age 45 to 54 | 11.5% | 14.0% | 12.6% |
| Age 55 to 59 | 5.7% | 6.3% | 6.7% |
| Age 60 to 64 | 5.6% | 6.5% | 6.3% |
| Age 65 to 74 | 9.5% | 6.5% | 9.6% |
| Age 75 to 84 | 4.6% | 3.0% | 4.5% |
| Age 85 and over | 0.7% | 1.0% | 1.9% |
| space1 | | | |
| Race | | | |
| | St. Marys, GA | Hilliard, OH | United States |
| White | 73.9% | 81.3% | 59.4% |
| Black | 13.1% | 4.4% | 12.2% |
| Asian | 2.0% | 5.8% | 5.6% |
| Native American | 0.7% | 0.0% | 0.6% |
| Hawaiian, Pacific Islander | 0.1% | 0.0% | 0.2% |
| Other | 0.1% | 0.3% | 0.4% |
| Two or More Races | 3.4% | 4.0% | 3.2% |
| Hispanic | 6.7% | 4.1% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | St. Marys, GA | Hilliard, OH | United States |
| Married Population | 54.7% | 62.5% | 49.8% |
| Currently Married | 50.9% | 61.8% | 48.0% |
| Married but Separated | 3.8% | 0.6% | 1.8% |
| Single Population | 45.3% | 37.5% | 50.2% |
| Never Married | 27.2% | 26.3% | 33.8% |
| Divorced | 12.8% | 7.8% | 10.8% |
| Widowed | 5.3% | 3.4% | 5.6% |
| space5 | | | |
| Household Size | 2.58 | 2.57 | 2.60 |
| Households | 7,020 | 13,782 | 124,010,992 |
| Family Households | 4,890 | 10,116 | 80,755,759 |
| Married couple, w/children | 30.2% | 38.5% | 30.5% |
| Married couple, no children | 39.7% | 44.5% | 42.9% |
| Non Family Households | 2,130 | 3,666 | 43,255,233 |
| Single householder, w/children | 20.7% | 11.1% | 15.8% |
| Single householder, no children | 9.4% | 5.8% | 10.8% |