We serve Oshawa but also the entire Regional Municipality of Durham. Oshawa is a city in Ontario, Canada. Which is located in Southern Ontario. It is also part of the Greater Toronto Area (GTA) and the Golden Horseshoe. Oshawa is the largest municipality in Durham. Oshawa is bordered by Coates Rd W in the north. Lake Ontario in the south. Boundary Rd in the west. Townline Rd in the east. The city proportion of Oshawa excluding the country region is 145.68 km2.