Lac MacMahon is a Lake located in Rivière-Koksoak; Kativik, Quebec.

• Latitude: 57° 3' 59'' North   (decimal: 57.0663889)
• Longitude: 72° 33' 13'' West   (decimal: -72.5536111)
• Topography Feature Category: Lake
• Geographical Feature: Lac
• Canadian Province/Territory: Quebec
• Location: Rivière-Koksoak; Kativik
• Atlas of Canada Locator Map: Lac MacMahon
• GPS Coordinate Locator Map: Lac MacMahon Lat/Long