Lac Onésime is a Lake located in Mont-Valin; Le Fjord-du-Saguenay, Quebec.

• Latitude: 49° 11' 43'' North   (decimal: 49.1952778)
• Longitude: 70° 56' 39'' West   (decimal: -70.9441667)
• Topography Feature Category: Lake
• Geographical Feature: Lac
• Canadian Province/Territory: Quebec
• Location: Mont-Valin; Le Fjord-du-Saguenay
• Atlas of Canada Locator Map: Lac Onésime
• GPS Coordinate Locator Map: Lac Onésime Lat/Long