Zionsville, IN has a population of 25,709 and is the 1,674th largest city in the United States. The population density is 480 per sq mi which is 168% higher than the Indiana average and 430% higher than the national average. The median age in Zionsville is 38 which is approximately 3% higher than the Indiana average of 37. In Zionsville, 71% of the population over 15 years of age are married, 94% speak English and 1% speak Spanish. 55% of Zionsville residents were born in Indiana, 38% were born out of state, 1% were born outside of the United States and 6% were foreign born.