Notre Dame Island is an artificial island in the Saint Lawrence River in Montreal, Quebec, Canada. It is immediately to the east of Saint Helen's Island and west of the Saint Lawrence Seaway and the city of Saint-Lambert on the south shore. Together with Saint Helen's Island, it makes up Parc Jean-Drapeau, which forms part of the Hochelaga Archipelago. To the southeast, the island is connected to the embankment separating the seaway and Lachine Rapids.

An artificial island is an island that has been constructed by humans rather than formed through natural processes. Other definitions may suggest that artificial islands are lands with the characteristics of human intervention in their format process, while others argue that artificial islands are created by expanding existing islets, constructing on existing reefs, or amalgamating several islets together. Although constructing artificial islands is not a modern phenomenon, there is no definite legal definition of it. Artificial islands may vary in size from small islets reclaimed solely to support a single pillar of a building or structure to those that support entire communities and cities. Archaeologists argue that such islands were created as far back as the Neolithic era. Early artificial islands included floating structures in still waters or wooden or megalithic structures erected in shallow waters.