A member of the Canadian Arctic Archipelago, Prince Patrick Island is the westernmost of the Queen Elizabeth Islands in the Northwest Territories of Canada. The area of the island is , making it the 55th largest island in the world and Canada's 14th largest island. It has historically been icebound all year, making it one of the most inaccessible parts of Canada.
Located at the entrance of the McClure Strait, Prince Patrick Island is uninhabited and there are no known communities, past or present. A High Arctic Weather Station (H.A.W.S.) called Mould Bay was opened in 1948 as part of a joint Canada-U.S. military effort to support a weather station network. It had a temporary staff of between 10 and 40 people. The station was closed in 1997 owing to budget cuts and replaced with an automated weather station at a new location on the airstrip below the station, ending the continuous weather record of 1948-1997. The buildings still stand, but as of 2007 most have deteriorated to an unrepairable state.
The island rises to only about , and the area is seismically active.
Prince Patrick Island is the setting for a work of fiction, the novel The Lost Ones (1961) by Ian Cameron (Donald G. Payne). It was filmed as the Walt Disney Pictures film The Island at the Top of the World in 1970. The novel tells of a lost colony of Vikings living in a lost valley in the island, which, thanks to the volcanoes on the island, is warm and habitable.