plains in Québec region, southern Quebec province, Canada. The plains lie at the western edge of the old walled city, overlooking the St. Lawrence River. The plateau was the scene of a battle (Sept. 13, 1759) between the French under the Marquis de Montcalm and the British under James Wolfe in which both leaders were killed but which secured Quebec for the British. Named for Abraham Martin, a ship's pilot who formerly owned part of the land, the plains are now a national historic park.