Ontario Highway 406

Ontario Highway 406

King's Highway 406, commonly referred to as Highway 406, is a 400-series highway in the Canadian province of Ontario connecting Welland with St. Catharines. It is the only 400-series highways with at-grade crossings.

Highway 406 is the primary north-south route though the central portion of the Niagara Peninsula, connecting Welland, Thorold and downtown St. Catharines to the Queen Elizabeth Way (QEW). The section through St. Catharines wraps through the Twelve Mile Creek valley in a winding route, and is therefore posted at 80 km/h (50 mph) rather than the typical 100 km/h (60 mph) speed limit.

Construction of Highway 406 began in 1963. The first section opened between St. Davids Road and Geneva Street on December 7, 1965, followed by a southward extension to Beaverdams Road in late 1969. The route was later extended south as a Super two to Merritt Road where it became Highway 58. In 1977, construction began to connect the freeway with the QEW; this was completed in late 1984. Construction on the route resumed in 1987 near Welland, connecting the route with East Main Street in Welland, completed during the mid-1990s.

In 2009 construction resumed on the highway to expand the remaining two lane sections to a four lane divided freeway, with the existing route becoming the southbound lanes of the new freeway. The southern terminus in Welland will be converted to a roundabout while the remaining at-grade intersections will be rebuilt as interchanges. This work is scheduled for completion in 2013.