The Rivière à l'Orme (English: Elm River) is a tributary of the Lac des Deux Montagnes, flowing into the territory of Pierrefonds, Quebec and Senneville, Quebec, in the city of Montreal, in Quebec, in Canada. The course of the river mainly passes through urban areas with urban park areas. Annually, the surface of the river is generally frozen from mid-December to late March, however, the period of safe ice circulation is usually from late December to mid-March.