A castaway is a person who is cast adrift or ashore. While the situation usually happens after a shipwreck, some people voluntarily stay behind on a desert island, either to evade captors or the world in general. A person may also be left ashore as punishment (marooned).

An uninhabited island, desert island, or deserted island, is an island, islet or atoll that is not permanently populated by humans. Uninhabited islands are often depicted in films or stories about shipwrecked people, and are also used as stereotypes for the idea of "paradise". Some uninhabited islands are protected as nature reserves, and some are privately owned. Devon Island in Canada's far north is the largest uninhabited island in the world.