| | Brunswick, GA | St. Marys, GA | United States |
| Population | 14,774 | 18,200 | 329,725,481 |
| Female Population | 55.3% | 49.9% | 50.5% |
| Male Population | 44.7% | 50.1% | 49.5% |
| Median Age | 36.3 | 35 | 38.4 |
| space3 | | | |
| Population - 2010 | 15,316 | 17,267 | 309,327,143 |
| Population - 2000 | 15,600 | 13,761 | 285,036,114 |
| Population - 1990 | 16,433 | 8,187 | 251,960,433 |
| Pop. 2000 to Now | 4.4% | 37.0% | 15.6% |
| Pop. 1990 to Now | -0.9% | 130.3% | 30.8% |
| space4 | | | |
| Population Density | 866.1 | 797.5 | 93.4 |
| Land Area | 17.1 | 22.8 | 3,531,905.4 |
| Water Area | 8.2 | 2.2 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | Brunswick, GA | St. Marys, GA | United States |
| Age 0 to 4 | 8.4% | 7.5% | 5.9% |
| Age 5 to 9 | 5.7% | 5.8% | 6.1% |
| Age 10 to 14 | 5.1% | 7.4% | 6.6% |
| Age 15 to 17 | 4.1% | 5.0% | 3.9% |
| Age 18 to 20 | 4.3% | 4.8% | 4.0% |
| Age 21 to 24 | 5.5% | 5.0% | 5.2% |
| Age 25 to 34 | 15.6% | 14.5% | 13.8% |
| Age 35 to 44 | 12.1% | 12.4% | 12.9% |
| Age 45 to 54 | 8.8% | 11.5% | 12.6% |
| Age 55 to 59 | 7.1% | 5.7% | 6.7% |
| Age 60 to 64 | 6.5% | 5.6% | 6.3% |
| Age 65 to 74 | 10.6% | 9.5% | 9.6% |
| Age 75 to 84 | 3.0% | 4.6% | 4.5% |
| Age 85 and over | 3.3% | 0.7% | 1.9% |
| space1 | | | |
| Race | | | |
| | Brunswick, GA | St. Marys, GA | United States |
| White | 31.0% | 73.9% | 59.4% |
| Black | 59.6% | 13.1% | 12.2% |
| Asian | 1.8% | 2.0% | 5.6% |
| Native American | 0.3% | 0.7% | 0.6% |
| Hawaiian, Pacific Islander | 0.1% | 0.1% | 0.2% |
| Other | 0.0% | 0.1% | 0.4% |
| Two or More Races | 0.7% | 3.4% | 3.2% |
| Hispanic | 6.3% | 6.7% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | Brunswick, GA | St. Marys, GA | United States |
| Married Population | 26.5% | 54.7% | 49.8% |
| Currently Married | 24.2% | 50.9% | 48.0% |
| Married but Separated | 2.3% | 3.8% | 1.8% |
| Single Population | 73.5% | 45.3% | 50.2% |
| Never Married | 45.8% | 27.2% | 33.8% |
| Divorced | 18.2% | 12.8% | 10.8% |
| Widowed | 9.6% | 5.3% | 5.6% |
| space5 | | | |
| Household Size | 2.54 | 2.58 | 2.60 |
| Households | 5,616 | 7,020 | 124,010,992 |
| Family Households | 3,226 | 4,890 | 80,755,759 |
| Married couple, w/children | 8.2% | 30.2% | 30.5% |
| Married couple, no children | 29.5% | 39.7% | 42.9% |
| Non Family Households | 2,390 | 2,130 | 43,255,233 |
| Single householder, w/children | 41.8% | 20.7% | 15.8% |
| Single householder, no children | 20.4% | 9.4% | 10.8% |