Editing Island of Montreal (section)

==Physical geography==
The island is approximately {{convert|50|km|mi|abbr=on}} long and {{convert|16|km|mi|abbr=on}} wide at its widest point, and has a shoreline of {{convert|266|km|mi|abbr=on}}. It is the second largest island in the [[Saint Lawrence River]], after [[Anticosti Island]] in the [[Gulf of Saint Lawrence]]. The Island of Montreal is the largest island in the [[Hochelaga Archipelago]], which is formed by the confluence of the Ottawa and St. Lawrence rivers.

[[File:Île de Montréal.png|thumb|350px|center|The Island of Montreal is a Croissant-shaped island, part of the [[Hochelaga Archipelago]].]]
Near the Ottawa shore at the western end of island, the Ottawa River widens into [[Lac des Deux-Montagnes]]. A natural watercourse there, between the island and [[Île Perrot]], has been improved by the island's [[Sainte-Anne-de-Bellevue Canal]]. These waterways, connecting Lac des Deux-Montagnes with [[Lake Saint-Louis]], constitute one of the places where the Ottawa flows into the St. Lawrence.

North of the island's western end, Lac des Deux-Montagnes flows into [[Rivière des Prairies]], still part of the Ottawa. The Prairies separates the island from the other major part of the Hochelaga Archipelago including [[Île Bizard]] and [[Île Jésus]]. After coursing about {{convert|55|km|mi|abbr=on}}, the Prairie, at the northeastern tip of the island, joins the St. Lawrence.

The St. Lawrence coast of the island faces a variable waterway. In the southwest, the St. Lawrence River widens into Lake Saint-Louis as it approaches the island. Around a southern point near the center of the island, the St. Lawrence narrows into the [[Lachine Rapids]], then widens into the [[Bassin de La Prairie]] past that southern point, and narrows again at the Montreal neighborhood of Cite Du Havre before flowing towards [[Quebec City, Quebec|Quebec City]] and the [[Atlantic Ocean]]. The [[Lachine Canal]] on the island bypasses this complex part of the river. Neighboring islands in the St. Lawrence include [[Saint Helen's Island]], [[Notre Dame Island]], and [[Nuns' Island]].

[[File:Plan_de_partie_de_l_isle_de_Monreal.jpg|thumb|right|18th-century map of [[Lake St Pierre]]]]
The [[topography]] of the island has been significantly altered by human activity, as evidenced by historical maps that name a lake St. Pierre in the island.<ref>{{Cite web |url=http://undermontreal.com/riviere-st-pierre-part-i-start-to-finish/ |title="Following Rivière St. Pierre". Author Andrew Emond. |access-date=2018-01-06 |archive-date=2018-01-07 |archive-url=https://web.archive.org/web/20180107071147/http://undermontreal.com/riviere-st-pierre-part-i-start-to-finish/ |url-status=dead }}</ref>  This lake, and several other watercourses, have been drained or covered over as the city developed, while areas on the island's shores have been [[land reclamation|reclaimed]] and extended. The southwest of the island is separated by the [[Lachine Canal]] between [[Lachine, Quebec|Lachine]] and Montreal's [[Old Port of Montreal|Old Port]]; this portion of the island is partially divided further by the Canal de l'Aqueduc, running roughly parallel to the Lachine Canal, beginning in the borough of [[LaSalle (Montreal)|LaSalle]] and continuing between the boroughs of [[Le Sud-Ouest]] and [[Verdun (Montreal)|Verdun]].

Most of the bedrock of the island consists of [[Chazy limestone]], with some [[Utica shale]]. At the centre of the island stand the three peaks of [[Mount Royal]], a [[intrusion|volcanic intrusion]] (not an [[extinct volcano]], contrary to popular belief). This short mountain (elevation {{convert|233|m|ft|abbr=off}} is a member of, and gives its name to, the [[Monteregian Hills]].