King's Highway 413, known as the GTA West Corridor or GTA West until 2021, is a proposed 400-series highway and bus transitway in the western Greater Toronto Area of the Canadian province of Ontario. The approximately 52-kilometre (32 mi) route is currently undergoing planning and analysis under an environmental impact assessment (EA) by both the Ministry of Transportation of Ontario (MTO) and the Government of Ontario, as well as the Impact Assessment Agency of Canada. If approved, a new four-to-six lane controlled-access highway would be built between the existing interchange of Highway 401 and the 407 ETR at the Halton–Peel boundary, and Highway 400 north of Vaughan. In addition, two new extensions would be built to connect Highway 410 and Highway 427 with Highway 413.