 The northern section of Highway 58 begins at an intersection with the western terminus of Highway 20 , approximately 3 @.@ 5 kilometres ( 2 @.@ 2 mi ) east of Highway 406 , within Thorold . South of this intersection , the road that carries Highway 58 continues as Niagara Regional Road 82 , whereas west of the intersection the road that carries Highway 20 , Lundy 's Lane , continues as Niagara Regional Road 58 through Allanburg . Highway 58 proceeds north , at first along an established concession road , before branching to the east on its own alignment known as Davis Road . The route crosses several flooded valleys that form part of the Welland Canal before arriving at Thorold Stone Road , at which point Highway 58 turns west and enters the Thorold Tunnel , descending beneath the canal . 
