| | St. Marks, FL | Panama City, FL | United States |
| Population | 298 | 34,521 | 329,725,481 |
| Female Population | 52.4% | 52.8% | 50.5% |
| Male Population | 47.7% | 47.2% | 49.5% |
| Median Age | 63.4 | 39.2 | 38.4 |
| space3 | | | |
| Population - 2010 | 293 | 34,695 | 309,327,143 |
| Population - 2000 | 272 | 36,417 | 285,036,114 |
| Population - 1990 | 307 | 34,378 | 251,960,433 |
| Pop. 2000 to Now | 22.4% | -7.4% | 15.6% |
| Pop. 1990 to Now | 8.5% | -1.9% | 30.8% |
| space4 | | | |
| Population Density | 152.1 | 986.3 | 93.4 |
| Land Area | 2.0 | 35.0 | 3,531,905.4 |
| Water Area | 0.0 | 6.2 | 264,836.8 |
| space | | | |
| Est. Total Population By Age | | | |
| | St. Marks, FL | Panama City, FL | United States |
| Age 0 to 4 | 1.7% | 6.9% | 5.9% |
| Age 5 to 9 | 0.0% | 5.8% | 6.1% |
| Age 10 to 14 | 3.0% | 6.5% | 6.6% |
| Age 15 to 17 | 0.7% | 3.1% | 3.9% |
| Age 18 to 20 | 2.3% | 3.0% | 4.0% |
| Age 21 to 24 | 1.7% | 5.0% | 5.2% |
| Age 25 to 34 | 6.7% | 14.9% | 13.8% |
| Age 35 to 44 | 5.4% | 11.6% | 12.9% |
| Age 45 to 54 | 16.8% | 11.7% | 12.6% |
| Age 55 to 59 | 6.4% | 6.0% | 6.7% |
| Age 60 to 64 | 6.7% | 6.7% | 6.3% |
| Age 65 to 74 | 26.2% | 10.5% | 9.6% |
| Age 75 to 84 | 22.5% | 5.8% | 4.5% |
| Age 85 and over | 0.0% | 2.6% | 1.9% |
| space1 | | | |
| Race | | | |
| | St. Marks, FL | Panama City, FL | United States |
| White | 96.0% | 62.0% | 59.4% |
| Black | 0.0% | 21.5% | 12.2% |
| Asian | 0.0% | 1.3% | 5.6% |
| Native American | 0.0% | 0.2% | 0.6% |
| Hawaiian, Pacific Islander | 0.0% | 0.2% | 0.2% |
| Other | 0.0% | 1.4% | 0.4% |
| Two or More Races | 4.0% | 5.0% | 3.2% |
| Hispanic | 0.0% | 8.4% | 18.4% |
| space2 | | | |
| Marriage & Family | | | |
| | St. Marks, FL | Panama City, FL | United States |
| Married Population | 63.0% | 42.7% | 49.8% |
| Currently Married | 61.3% | 40.4% | 48.0% |
| Married but Separated | 1.8% | 2.3% | 1.8% |
| Single Population | 37.0% | 57.3% | 50.2% |
| Never Married | 6.3% | 32.4% | 33.8% |
| Divorced | 22.9% | 15.9% | 10.8% |
| Widowed | 7.7% | 9.0% | 5.6% |
| space5 | | | |
| Household Size | 1.96 | 2.32 | 2.60 |
| Households | 152 | 14,667 | 124,010,992 |
| Family Households | 117 | 8,359 | 80,755,759 |
| Married couple, w/children | 4.3% | 24.1% | 30.5% |
| Married couple, no children | 73.5% | 38.3% | 42.9% |
| Non Family Households | 35 | 6,308 | 43,255,233 |
| Single householder, w/children | 12.0% | 23.8% | 15.8% |
| Single householder, no children | 10.3% | 13.9% | 10.8% |