Belleville is a city in Ontario, Canada situated on the eastern end of Lake Ontario, located at the mouth of the Moira River and on the Bay of Q…Belleville is a city in Ontario, Canada situated on the eastern end of Lake Ontario, located at the mouth of the Moira River and on the Bay of Quinte. Belleville is between Ottawa and Toronto, along the Quebec City-Windsor Corridor. Its population as of the 2021 Canadian census was 55,071. It is the seat of Hastings County, but politically independent of it, and is the centre of the Bay of Quinte Region.