Lac Thonac is a Lake located in Lac-Ashuapmushuan; Le Domaine-du-Roy, Quebec and has an elevation of 449 meters.

• Latitude: 48° 58' 21'' North   (decimal: 48.9725)
• Longitude: 73° 59' 38'' West   (decimal: -73.9938889)
• Topography Feature Category: Lake
• Geographical Feature: Lac
• Canadian Province/Territory: Quebec
• Elevation: 449 meters
• Location: Lac-Ashuapmushuan; Le Domaine-du-Roy
• Atlas of Canada Locator Map: Lac Thonac
• GPS Coordinate Locator Map: Lac Thonac Lat/Long