An image of Antarctica differentiating its landmass (dark grey) from its ice shelves (minimum extent, light grey, and maximum extent, white)
A landmass, or land mass, is a large region or area of land that is in one piece and not broken up by oceans.[1][2] The term is often used to refer to lands surrounded by an ocean or sea, such as a continent or a large island.[3][4] In the field of geology, a landmass is a defined section of continental crust extending above sea level.[5]
Continents are often thought of as distinct landmasses and may include any islands that are part of the associated continental shelf. When multiple continents form a single contiguous land connection, the connected continents may be viewed as a single landmass. Earth's largest landmasses are (starting with largest):[6][7][8]
Continental landmasses are not usually classified as islands despite being completely surrounded by water.[Note 1] However, because the definition of continent varies between geographers, the Americas are sometimes defined as two separate continents while mainland Australia is sometimes defined as an island as well as a continent. Nevertheless, for the purposes of this list, mainland Australia along with the other major landmasses have been listed as continental landmasses for comparison. The figures are approximations and are for the four major continental landmasses only.[Note 2] The artificial Panama and Suez canals are disregarded, as they are not natural waters that separate the continents.
^The United States Geological Survey is a notable exception. The United States-based scientific agency considers all landmasses surrounded by ocean water, including continental mainlands, as islands. Under their definition, Africa, Australia, Eurasia, North America, and South America are classified as continental mainland islands.[9]
^Physiographically, there are only four continents (including offshore continental islands which sit on the nearby continental shelves) that are completely surrounded by water: Afro-Eurasia (57% of the global land area), the Americas (28.5%), Antarctica (9%), and Australia (5%). The remaining 0.5% is made up of remote oceanic islands, mostly scattered within Oceania in the central and south Pacific Ocean.[10]
^Including landmasses which are above water and over 2,500,000 km2 (970,000 sq mi). The submerged continent of Zealandia (approx. 5,000,000 km2 (1,900,000 sq mi)) is excluded.[11]
^Figure derived from the Global Islands Explorer website, by adding the areas of mainland Africa (29,370,907 km2 (11,340,171 sq mi)) and mainland Eurasia (50,439,819 km2 (19,474,923 sq mi)).
^Two states on mainland Africa and five states on mainland Eurasia (three states on continental Asia[Note 9] and two states on continental Europe).
^Figure derived from the Global Islands Explorer website, by adding the areas of mainland North America (20,090,075 km2 (7,756,821 sq mi)) and mainland South America (17,609,548 km2 (6,799,084 sq mi)).
^Depending on the definition, a significant portion of Panama (land east of the Panama Canal) could be considered a part of mainland South America.
^Ten countries on mainland North America[Note 12] and twelve countries on mainland South America.
^Antarctica is a special case, for if its ice is considered not as land, but as water, it is not a single landmass, but several landmasses of much smaller area, since the ice-bedrock boundary is below sea level in many regions of the continent.[12] If its ice cover were to be lifted, some rocks that are currently below sea level would rise as the weight of the ice would be removed,[13] although this would in part be counteracted, and in some areas of the continent overtaken, by eustatic rises in sea level.[14]
^Area of mainland Antarctica, without the ice shelves and nearby islands.[15]
^Mainland Australia is more than three times the size of Greenland, the largest island.[16] Australia is sometimes dubbed "The Island Continent" or "Earth's largest island, but its smallest continent".[17]
^Figure derived from the Geoscience Australia website, the area of mainland Tasmania (64,519 km2 (24,911 sq mi)) has been deducted.[18] The Global Islands Explorer website has given a slightly larger figure of 7,618,696 km2 (2,941,595 sq mi) for the area of mainland Australia.
^R.W. McColl, ed. (2005). "continents". Encyclopedia of World Geography. Vol. 1. Facts on File, Inc. p. 215. ISBN978-0-8160-7229-3. Retrieved 25 August 2022. And since Africa and Asia are connected at the Suez Peninsula, Europe, Africa, and Asia are sometimes combined as Afro-Eurasia or Eurafrasia. The International Olympic Committee's official flag, containing [...] the single continent of America (North and South America being connected as the Isthmus of Panama).
