Ontario Highway 404

Ontario Highway 404

King's Highway 404, also known as Highway 404 and colloquially as the four-oh-four, is a 400-series highway in the Canadian province of Ontario connecting Highway 401 and the Don Valley Parkway (DVP) in Toronto with Newmarket. The controlled-access highway also connects with Highway 407 in Markham.

Construction on the freeway began soon after the completion of the Don Valley Parkway, with the first section south of Steeles Avenue opening in 1977. Over the next twelve years, the Ministry of Transportation of Ontario (MTO) undertook a continuous construction program to build the freeway to Davis Drive in Newmarket. This was completed on October 24, 1989. Since then, the route has been expanded in width and extended by 2 km (1.2 mi) to Green Lane, an east-west road in the town of East Gwillimbury. A northward extension to Ravenshoe Road near Keswick is currently under construction, with completion tentatively scheduled for December 2012. This 13.5 km (8.4 mi) route is the first part of a proposed extension to southeast of Beaverton.

Highway 404 is one of several freeways in the Greater Toronto Area (GTA) with High-Occupancy Vehicle (HOV) lanes; the southbound lane was one of the initial projects in the province and opened on December 13, 2005. The northbound lane opened on July 23, 2007.