Lac Castonguay is a Lake located in Amqui; La Matapédia, Quebec and has an elevation of 201 meters.

• Latitude: 48° 26' 58'' North   (decimal: 48.4494444)
• Longitude: 67° 27' 1'' West   (decimal: -67.4502777)
• Topography Feature Category: Lake
• Geographical Feature: Lac
• Canadian Province/Territory: Quebec
• Elevation: 201 meters
• Location: Amqui; La Matapédia
• Atlas of Canada Locator Map: Lac Castonguay
• GPS Coordinate Locator Map: Lac Castonguay Lat/Long