Lac Marthe is a Lake located in Lac-au-Brochet; La Haute-Côte-Nord, Quebec and has an elevation of 408 meters.

• Latitude: 49° 1' 47'' North   (decimal: 49.0297580)
• Longitude: 69° 17' 14'' West   (decimal: -69.2872766)
• Topography Feature Category: Lake
• Geographical Feature: Lac
• Canadian Province/Territory: Quebec
• Elevation: 408 meters
• Location: Lac-au-Brochet; La Haute-Côte-Nord
• Atlas of Canada Locator Map: Lac Marthe
• GPS Coordinate Locator Map: Lac Marthe Lat/Long