Ontario Highway 406

Highway 406
Highway 406 highlighted in red
Route information
Maintained by Ministry of Transportation of Ontario
Length	26.0 km[1] (16.2 mi)
Existed	December 7, 1965[2]–present
Major junctions
North end	Queen Elizabeth Way – St. Catharines
Major intersections	Highway 58 – Thorold
South end	Regional Road 27 – Welland
Location
Country	Canada
Province	Ontario
Highway system
Ontario provincial highways Current Former 400-series
← Highway 405 → 407 ETR / Highway 407

King's Highway 406 (pronounced "four-oh-six"), commonly referred to as Highway 406, is a 400-series highway in the Canadian province of Ontario. The primary north–south route through the central portion of the Niagara Peninsula, Highway 406 connects Welland, Thorold and downtown St. Catharines to the Queen Elizabeth Way (QEW).

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 resumed in 1987 to extend Highway 406 further south to Welland, albeit as a super two, where it ended at a signalized intersection at East Main Street and this was completed in 1995.^[3] 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 was converted to a roundabout while the remaining at-grade intersections were rebuilt as interchanges. ^[3]