Lac Halfmoon is a Lake located in Brownsburg-Chatham; Argenteuil, Quebec.

• Latitude: 45° 41' 49'' North   (decimal: 45.6968999)
• Longitude: 74° 30' 57'' West   (decimal: -74.5158000)
• Topography Feature Category: Lake
• Geographical Feature: Lac
• Canadian Province/Territory: Quebec
• Location: Brownsburg-Chatham; Argenteuil
• GPS Coordinate Locator Map: Lac Halfmoon Lat/Long