Summerville, SC has a population of 47,919 and is the 862nd largest city in the United States. The population density is 2,480 per sq mi which is 1581% higher than the South Carolina average and 2638% higher than the national average. The median age in Summerville is 36 which is approximately 8% lower than the South Carolina average of 39. In Summerville, 56% of the population over 15 years of age are married, 94% speak English and 4% speak Spanish. 44% of Summerville residents were born in South Carolina, 49% were born out of state, 2% were born outside of the United States and 5% were foreign born.