Fort Polk South, LA has a population of 9,219 and is the 4,185th largest city in the United States. The population density is 1,497 per sq mi which is 1588% higher than the Louisiana average and 1552% higher than the national average. The median age in Fort Polk South is 22 which is approximately 38% lower than the Louisiana average of 36. In Fort Polk South, 65% of the population over 15 years of age are married, 83% speak English and 9% speak Spanish. 13% of Fort Polk South residents were born in Louisiana, 75% were born out of state, 5% were born outside of the United States and 6% were foreign born.