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

• Latitude: 56° 34' 7'' North   (decimal: 56.5686111)
• Longitude: 70° 50' 3'' West   (decimal: -70.8341667)
• Topography Feature Category: Lake
• Geographical Feature: Lac
• Canadian Province/Territory: Quebec
• Location: Rivière-Koksoak; Kativik
• GPS Coordinate Locator Map: Lac Great Long Lat/Long