Grand lac Thomas is a Lake located in Rivière-Mistassini; Maria-Chapdelaine, Quebec and has an elevation of 435 meters.

• Latitude: 49° 57' 24'' North   (decimal: 49.9566667)
• Longitude: 72° 10' 39'' West   (decimal: -72.1775)
• Topography Feature Category: Lake
• Geographical Feature: Lac
• Canadian Province/Territory: Quebec
• Elevation: 435 meters
• Location: Rivière-Mistassini; Maria-Chapdelaine
• Atlas of Canada Locator Map: Grand lac Thomas
• GPS Coordinate Locator Map: Grand lac Thomas Lat/Long