Which major city lies on an island in the St. Lawrence River?

Montreal is the major city that lies on an island in the St. Lawrence River. It is actually the largest city in Quebec of Canada. It is actually a place where French speaking people are maximum and the city is named after Mount Royal. The official language of this city is French because 56.9% of the people living in this city speak the French language. It has ben known from Archeological facts that the native people of First Nations occupied this city about 4000 years ago. They started the cultivation of maize for the first time during 1000 AD.