St. Charles
- County:
- Bear Lake County
- County Seat:
- No
- Area (mi²):
- 0.733
- State:
- Idaho
St. Charles is a city located in Bear Lake County, Idaho. St. Charles has a 2026 population of 185. St. Charles is currently declining at a rate of -0.54% annually but its population has increased by 13.5% since the most recent census, which recorded a population of 163 in 2020.
The median age in St. Charles is 34.1 years: 50.8 years for males, and 19.9 years for females. For every 100 females there are 126.6 males.