St. Charles is a town in the Canadian province of Ontario, located in the Sudbury District.

It was created on January 1, 1999, by the amalgamation of the incorporated townships of Casimir, Jennings, and Appleby, as well as a strip of unorganized territory on the West Arm of Lake Nipissing.

Along with the municipalities of Markstay-Warren and French River, it is part of the region known as Sudbury East.

Franco-Ontarians, or Ontarians who speak French as their mother tongue, make up 41% of the population.

[1] In addition to the primary townsite at St. Charles, the municipality also includes the smaller communities of Casimir and West Arm.