Cornwall is a city in Eastern Ontario, Canada, situated where the provinces of Ontario and Quebec and the U.S. state of New York converge. It is the seat of the United Counties of Stormont, Dundas, and Glengarry and is Ontario's easternmost city. Cornwall is named after the English Duchy of Cornwall; the city's coat of arms is based on that of the duchy with its colours reversed and the addition of a "royal tressure," a Scottish symbol of royalty.