Lac au Castor is a Lake located in Lac-Nilgaut; Pontiac, Quebec and has an elevation of 374 meters.

• Latitude: 46° 52' 39'' North   (decimal: 46.8775)
• Longitude: 77° 13' 47'' West   (decimal: -77.2297221)
• Topography Feature Category: Lake
• Geographical Feature: Lac
• Canadian Province/Territory: Quebec
• Elevation: 374 meters
• Location: Lac-Nilgaut; Pontiac
• Atlas of Canada Locator Map: Lac au Castor
• GPS Coordinate Locator Map: Lac au Castor Lat/Long