Châteauguay

City in Châteauguay County, southern Québec, Canada, on Lake St-Louis (the St Lawrence River) and the mouth of the Châteauguay River, 19 km/12 mi southwest of Montréal; population (1991) 39,800. Traditionally an agricultural trade centre, it is now a residential suburb and fruit and dairy producing district, with some light manufactures.

On 26 October 1813, British and Indian troops repelled an invading US force along the River Châteauguay, near Ormstown, some 24 km/15 mi north of the New York border.

The River Châteauguay (in New York State, known as the Chateaugay River) rises at Chateaugay Lake, New York, USA, in the Adirondack Mountains, 40 km/25 mi west of Plattsburgh, and flows generally north-northwest into Québec, then northeast toward Montréal.