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

• Latitude: 55° 33' 19'' North   (decimal: 55.5554027)
• Longitude: 70° 14' 36'' West   (decimal: -70.2432941)
• Topography Feature Category: Lake
• Geographical Feature: Lac
• Canadian Province/Territory: Quebec
• Location: Rivière-Koksoak; Kativik
• Atlas of Canada Locator Map: Lac Sir-James
• GPS Coordinate Locator Map: Lac Sir-James Lat/Long