Regional Municipality of Niagara
Thorold, located on the brow of the Niagara Escarpment, soon became dominant and was incorporated as a village in 1850 and as a town in 1870. When the Regional Municipality of Niagara was formed in 1970, the Town of Thorold expanded to include the former Thorold Township. In 1975, the town became incorporated as the City of Thorold.