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

• Latitude: 48° 49' 14'' North   (decimal: 48.8205556)
• Longitude: 70° 50' 47'' West   (decimal: -70.8463889)
• Topography Feature Category: Lake
• Geographical Feature: Lac
• Canadian Province/Territory: Quebec
• Location: Mont-Valin; Le Fjord-du-Saguenay
• Atlas of Canada Locator Map: Lac Mustakis
• GPS Coordinate Locator Map: Lac Mustakis Lat/Long