The Chateauguay River is a tributary of the South Shore of the St. Lawrence River, flowing in: Clinton County and Franklin County, in the Adirondacks, in New York State, United States; the Le Haut-Saint-Laurent Regional County Municipality: crossing the municipalities of Huntingdon, Ormstown and Howick, in Montérégie region, Quebec, Canada; the MRC of Beauharnois-Salaberry Regional County Municipality: municipality of Sainte-Martine, in Montérégie; the MRC of Roussillon Regional County Municipality: city of Mercier, in Montérégie. Wikipedia