Atwater is a station on the Green Line of the Montreal Metro rapid transit system operated by the Société de transport de Montréal (STM). It is located on the border between the city of Westmount and the borough of Ville-Marie in Montreal, Quebec, Canada. The station opened on October 14, 1966, as part of the original network of the Metro; it was the western terminus of the Green Line until the extension to Angrignon in 1978.