St. Marks
- County:
- Sedgwick County
- County Seat:
- No
- Area (mi²):
- 0.977
- State:
- Kansas
St. Marks is a CDP located in Sedgwick County, Kansas. St. Marks has a 2025 population of 134. St. Marks is currently growing at a rate of 7.2% annually and its population has increased by 294.12% since the most recent census, which recorded a population of 34 in 2020.
The median age in St. Marks is 10.9 years: 10.2 years for males, and 0 years for females.