St. Simons, GA has a population of 13,480 and is the 3,104th largest city in the United States. The population density is 818 per sq mi which is 390% higher than the Georgia average and 803% higher than the national average. The median age in St. Simons is 54 which is approximately 49% higher than the Georgia average of 36. In St. Simons, 67% of the population over 15 years of age are married, 93% speak English and 3% speak Spanish. 42% of St. Simons residents were born in Georgia, 52% were born out of state, 2% were born outside of the United States and 4% were foreign born.