Orillia is a city in Ontario, Canada, about 30 km north-east of Barrie in Simcoe County. It is located at the confluence of Lake Couchiching and Lake Simcoe. Although it is geographically located within Simcoe County, the city is a single-tier municipality. It is part of the Huronia region of Central Ontario. The population in 2021 was 33,411.