St. Marys is a city located in Kansas. St. Marys has a 2020 population of 3,783. St. Marys is currently growing at a rate of 0.11% annually and its population has increased by 3.93% since the most recent census, which recorded a population of 3,640 in 2010. St. Marys reached it's highest population of 3,783 in 2021.
The average household income in St. Marys is $75,147 with a poverty rate of 4.48%. The median rental costs in recent years comes to $723 per month, and the median house value is $162,100. The median age in St. Marys is 25.1 years, 26.5 years for males, and 24.2 years for females.