Mainland is a name given to a large landmass in a region (as contrasted with a nearby island or islands),or to the largest of a group of islands in an archipelago. Sometimes its residents are called "Mainlanders". Because of its larger area, a mainland almost always has a much larger population than its associated islands, and mainlander culture and politics sometimes threaten to dominate those of the islands.

Prominent uses of the term include:

  • Mainland Argentina, as opposed to the disputed Falkland Islands and South Georgia and the South Sandwich Islands, and Tierra del Fuego. The term is discouraged by the residents of the Falkland Islands and South Georgia and the South Sandwich Islands, who are mainly British citizens.
  • Mainland Australia, as opposed to Tasmania.
  • Mainland Britain: (i.e. the island of Great Britain), as opposed to Northern Ireland, the Channel Islands or the Isle of Man. On the Isle of Wight in 1982, Paul Theroux overheard residents at Ventnor: "and now they were talking about 'the mainland', as if we were far at sea and not twenty minutes by ferry from Portsmouth".
  • Mainland Canada, as opposed to Prince Edward Island, Newfoundland, Cape Breton Island or Vancouver Island;
  • Mainland China (including the island of Hainan), as opposed to the special administrative regions of Hong Kong and Macau of the People's Republic of China (PRC), and the politically separate island of Taiwan and other small islands administered by the Republic of China (ROC);
  • Mainland Chile, as opposed to insular Chile (Easter Island, Sala y Gómez, Desventuradas Islands and Juan Fernández Islands). It is also used as opposed to Chiloé Island and Tierra del Fuego;
  • Mainland Denmark, as opposed to the Faroe Islands and Greenland;
  • Mainland Ecuador, as opposed to the Galapagos Islands;
  • Mainland Equatorial Guinea, usually called Río Muni, the part which is on the African continent, as opposed to the offshore islands;
  • Mainland Estonia, as opposed to Saaremaa, Hiiumaa and other Western Estonian islands;
  • Mainland Europe, another term for Continental Europe used in many parts of the English-speaking world, but generally not in the United Kingdom; usually in Great Britain, and sometimes in Ireland, mainland Europe is referred to as The Continent or just Europe.
  • Mainland Finland, as opposed to Åland Islands;
  • Mainland France (Le Continent), as opposed to Corsica; in relation to its Overseas Departments and Territories, the term Metropolitan France (France Métropolitaine) is more commonly used;
  • Mainland Greece (including and the island of Euboia), as opposed to the Greek Islands.
  • Mainland Ireland as opposed to its offshore islands. Note that "the mainland" in Northern Ireland is ambiguous between this sense and the preceding one; using the phrase to mean "Great Britain as opposed to Northern Ireland" is considered objectionable by many Nationalists. In Ireland the term "the mainland" is also used as an alternative means to refer to the land mass of Europe
  • Mainland India, as opposed to the union territories of Andaman and Nicobar Islands and Lakshadweep.
  • Mainland Italy, as opposed to Sardinia, Sicily, and other minor islands.
  • Mainland Japan and Honshū, as opposed to the rest of the Japanese islands (see also Home Islands);
  • Mainland Korea as opposed to Jeju and Ulleung Islands
  • Mainland Malaysia as opposed to Sabah, Sarawak and its other smaller islands such as Penang and Langkawi
  • Mainland Netherlands as opposed to Bonaire, Sint Eustatius and Saba.
  • The Nova Scotian mainland, as opposed to Cape Breton Island;
  • Mainland Portugal, or Continental Portugal (Portugal Continental), as opposed to Azores and Madeira Islands.
  • Mainland Scotland as opposed to its many offshore islands including the Western Isles and Orkney or Shetland.
  • Mainland Spain as opposed to the Balearic and Canary Islands, the North African cities of Ceuta and Melilla, the island of Alborán and other minor exclaves on Northern Africa (called the plazas de soberanía). In Spain the terms "España peninsular" or simply "La Península" are often used.
  • Mainland United States, as opposed to the state of Hawaii and overseas territories. The terms "U.S. Mainland" and "The Mainland" are commonly used in Hawaii, but less commonly on the U.S. mainland itself. The term "continental United States" is used, but is ambiguous in sometimes excluding Alaska and sometimes not. The term "contiguous United States" is more precise in excluding both Alaska and Hawaii. A common term used to refer to the continental U.S. excluding Alaska is "the lower 48", but Hawaii has a lower latitude than any other state. (The word "mainland" occurs numerous times in Hawaiian law, and apparently refers to any part of the United States outside of Hawaii.)
  • Mainland North America as opposed to Mainland United States includes the parts of the largest Island of North America that includes the mainland of Canada, the United States and Mexico.
  • The South Island of New Zealand is sometimes jocularly called the Mainland, especially by South Islanders. Though it has a far smaller population, it is slightly larger than the North Island. Mainland New Zealand more commonly refers to the North and South Island combined, as opposed to offshore islands such as Stewart Island, Waiheke Island, Great Barrier Island, and the Chatham Islands
  • The largest islands of the Orkney and Shetland Islands; see Mainland, Orkney and Mainland, Shetland.
  • Main or Big Land — in Russia — opposed to Minor Land, islands or another isolated territories, connected by water or by air, not by paved road.

The term is used on multiple levels. To someone in Tasmania, continental Australia is the mainland; but to residents of King Island, Flinders Island, and the other surrounding islands, Tasmania itself is the mainland.