Charleston, SC has a population of 129,888 and is the 205th largest city in the United States. The population density is 1,191 per sq mi which is 708% higher than the South Carolina average and 1215% higher than the national average. The median age in Charleston is 34 which is approximately 12% lower than the South Carolina average of 39. In Charleston, 46% of the population over 15 years of age are married, 95% speak English and 2% speak Spanish. 49% of Charleston residents were born in South Carolina, 45% were born out of state, 1% were born outside of the United States and 4% were foreign born.