High Quality Content by WIKIPEDIA articles! The Niagara Peninsula is the portion of Southern Ontario, Canada lying between the south shore of Lake Ontario and the north shore of Lake Erie. It stretches from the Niagara River in the east to Hamilton, Ontario in the west. The population of the peninsula is roughly 1,000,000 people. The region directly across the Niagara River and Lake Erie in New York State is known as the Niagara Frontier. Located in Western New York, the area forms a part of the broader Buffalo Niagara Region.