Lac Marsais is a Lake located in Lac-Legendre; Matawinie, Quebec and has an elevation of 478 meters.

• Latitude: 46° 41' 13'' North   (decimal: 46.6869865)
• Longitude: 74° 18' 50'' West   (decimal: -74.3137731)
• Topography Feature Category: Lake
• Geographical Feature: Lac
• Canadian Province/Territory: Quebec
• Elevation: 478 meters
• Location: Lac-Legendre; Matawinie
• Atlas of Canada Locator Map: Lac Marsais
• GPS Coordinate Locator Map: Lac Marsais Lat/Long