Sumter, SC has a population of 40,760 and is the 1,012th largest city in the United States. The population density is 1,253 per sq mi which is 749% higher than the South Carolina average and 1282% higher than the national average. The median age in Sumter is 35 which is approximately 11% lower than the South Carolina average of 39. In Sumter, 51% of the population over 15 years of age are married, 93% speak English and 3% speak Spanish. 62% of Sumter residents were born in South Carolina, 33% were born out of state, 2% were born outside of the United States and 4% were foreign born.