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. Technically an isthmus rather than a peninsula, 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.