St. John is a city located in Indiana. With a 2020 population of 18,917, it is the 48th largest city in Indiana and the 1933rd largest city in the United States. St. John is currently growing at a rate of 2.35% annually and its population has increased by 27.39% since the most recent census, which recorded a population of 14,850 in 2010. Spanning over 13 miles, St. John has a population density of 1,520 people per square mile.
The average household income in St. John is $124,158 with a poverty rate of 3.32%. The median rental costs in recent years comes to $799 per month, and the median house value is $283,000. The median age in St. John is 43.3 years, 42.9 years for males, and 43.6 years for females. For every 100 females there are 90.7 males.