Eastern Ontario (census population 1,603,625 in 2006) is a secondary region of Southern Ontario in the Canadian province of Ontario which lies in a wedge-shaped area between the Ottawa River and St. Lawrence River. It shares water boundaries with Quebec to the north and New York State to the east and south, as well as a small land boundary with the Vaudreuil-Soulanges region of Quebec to the east. Some sources may also include Hastings, Prince Edward, and sometimes even Northumberland in the definition of Eastern Ontario, but others classify them as Central Ontario.