Cours d'eau Castonguay is a River located in Saint-Ulric; Matane, Quebec.

• Latitude: 48° 44' 9'' North   (decimal: 48.7358762)
• Longitude: 67° 47' 19'' West   (decimal: -67.7886160)
• Topography Feature Category: River
• Geographical Feature: Cours d'eau agricole
• Canadian Province/Territory: Quebec
• Location: Saint-Ulric; Matane
• Atlas of Canada Locator Map: Cours d'eau Castonguay
• GPS Coordinate Locator Map: Cours d'eau Castonguay Lat/Long