Big Grassy River is a River located in Rainy River, Ontario and has an elevation of 344 meters.

• Latitude: 49° 5' 34'' North   (decimal: 49.0927777)
• Longitude: 94° 20' 28'' West   (decimal: -94.3411111)
• Topography Feature Category: River
• Geographical Feature: River
• Canadian Province/Territory: Ontario
• Elevation: 344 meters
• Location: Rainy River
• Atlas of Canada Locator Map: Big Grassy River
• GPS Coordinate Locator Map: Big Grassy River Lat/Long