Barrage Dempsey is a Hydraulic construction located in Lac-Nilgaut; Pontiac, Quebec.

• Latitude: 47° 1' 41'' North   (decimal: 47.0280556)
• Longitude: 77° 27' 5'' West   (decimal: -77.4513889)
• Topography Feature Category: Hydraulic construction
• Geographical Feature: Barrage
• Canadian Province/Territory: Quebec
• Location: Lac-Nilgaut; Pontiac
• Atlas of Canada Locator Map: Barrage Dempsey
• GPS Coordinate Locator Map: Barrage Dempsey Lat/Long