Lac au Masque is a Lake located in Rivière-Mistassini; Maria-Chapdelaine, Quebec.

• Latitude: 49° 47' 28'' North   (decimal: 49.7911734)
• Longitude: 72° 18' 18'' West   (decimal: -72.3050894)
• Topography Feature Category: Lake
• Geographical Feature: Lac
• Canadian Province/Territory: Quebec
• Location: Rivière-Mistassini; Maria-Chapdelaine
• Atlas of Canada Locator Map: Lac au Masque
• GPS Coordinate Locator Map: Lac au Masque Lat/Long