Sioux Center, IA has a population of 7,370 and is the 4,995th largest city in the United States. The population density is 1,184 per sq mi which is 2067% higher than the Iowa average and 1206% higher than the national average. The median age in Sioux Center is 27 which is approximately 28% lower than the Iowa average of 38. In Sioux Center, 58% of the population over 15 years of age are married, 87% speak English and 12% speak Spanish. 61% of Sioux Center residents were born in Iowa, 32% were born out of state, 0% were born outside of the United States and 7% were foreign born.