Lac Castagnet is a Lake located in Belle-Rivière; Lac-Saint-Jean-Est, Quebec and has an elevation of 420 meters.

• Latitude: 48° 5' 18'' North   (decimal: 48.0883333)
• Longitude: 71° 50' 29'' West   (decimal: -71.8413888)
• Topography Feature Category: Lake
• Geographical Feature: Lac
• Canadian Province/Territory: Quebec
• Elevation: 420 meters
• Location: Belle-Rivière; Lac-Saint-Jean-Est
• Atlas of Canada Locator Map: Lac Castagnet
• GPS Coordinate Locator Map: Lac Castagnet Lat/Long