Johnstown is a Unincorporated area located in Grenville, Ontario and has an elevation of 78 meters.

• Latitude: 44° 44' 53'' North   (decimal: 44.7480555)
• Longitude: 75° 28' 11'' West   (decimal: -75.4697222)
• Topography Feature Category: Unincorporated area
• Geographical Feature: Compact Rural Community
• Canadian Province/Territory: Ontario
• Elevation: 78 meters
• Location: Grenville
• Atlas of Canada Locator Map: Johnstown
• GPS Coordinate Locator Map: Johnstown Lat/Long