St. Charles is a city in Bear Lake County, Idaho, United States. Located near the northwestern shore of Bear Lake, its population was 131 at the 2010 census, down from 156 in 2000.
Ranching and recreation are the major influences on the community. Its small population live in houses scattered through a number of blocks of rustic streets interspersed with fields and agricultural buildings. A number of summer homes for visitors to the lake have added to the community. St. Charles sits at the mouth of St. Charles Canyon, a scenic inlet into the neighboring mountains, where hiking and camping opportunities are available.