Lac Castonguay is a Lake located in Madawaska, New Brunswick and has an elevation of 259 meters.

• Latitude: 47° 10' 59'' North   (decimal: 47.1829589)
• Longitude: 67° 44' 24'' West   (decimal: -67.7400285)
• Topography Feature Category: Lake
• Geographical Feature: Lac
• Canadian Province/Territory: New Brunswick
• Elevation: 259 meters
• Location: Madawaska
• Atlas of Canada Locator Map: Lac Castonguay
• GPS Coordinate Locator Map: Lac Castonguay Lat/Long