Ontario is not a city in Canada; it is a Province. Niagara Falls ( the waterfalls) is positioned in the Niagara River which separates the USA and Canada. There is a city named Niagara Falls in both New York State on the USA side of the river and a city named Niagara Falls on the Canadian side of the river which is in Province of Ontario. Buffalo New York is about 20 miles south of Niagara Falls NY. To get to the Canadian side of the Falls, you must cross an international border checkpoint and have your passport with you. It is a very short drive across the bridge from the USA to Canada at Niagara Falls.
