Lac Mathieu is a Lake located in Lac-Walker; Sept-Rivières, Quebec.

• Latitude: 50° 40' 45'' North   (decimal: 50.6791667)
• Longitude: 67° 24' 34'' West   (decimal: -67.4094444)
• Topography Feature Category: Lake
• Geographical Feature: Lac
• Canadian Province/Territory: Quebec
• Location: Lac-Walker; Sept-Rivières
• Atlas of Canada Locator Map: Lac Mathieu
• GPS Coordinate Locator Map: Lac Mathieu Lat/Long