Lac Sébastien is a Lake located in Lac-Ashuapmushuan; Le Domaine-du-Roy, Quebec and has an elevation of 385 meters.

• Latitude: 48° 7' 9'' North   (decimal: 48.1191667)
• Longitude: 72° 39' 25'' West   (decimal: -72.6569444)
• Topography Feature Category: Lake
• Geographical Feature: Lac
• Canadian Province/Territory: Quebec
• Elevation: 385 meters
• Location: Lac-Ashuapmushuan; Le Domaine-du-Roy
• Atlas of Canada Locator Map: Lac Sébastien
• GPS Coordinate Locator Map: Lac Sébastien Lat/Long