North Sioux City, SD has a population of 2,623 and is the 9,550th largest city in the United States. The population density is 1,153 per sq mi which is 10565% higher than the South Dakota average and 1173% higher than the national average. The median age in North Sioux City is 40 which is approximately 8% higher than the South Dakota average of 37. In North Sioux City, 47% of the population over 15 years of age are married, 98% speak English and 2% speak Spanish. 7% of North Sioux City residents were born in South Dakota, 92% were born out of state, 0% were born outside of the United States and 1% were foreign born.