This article contains a list of countries by length of coastline, in kilometers. Though the coastline paradox stipulates that coastlines do not have a well-defined length, there are various methods in use to measure coastlines through ratios and other metrics. A

coast A coast (coastline, shoreline, seashore) is the land next to the sea or the line that forms the boundary between the land and the ocean or a lake. Coasts are influenced by the topography of the surrounding landscape and by aquatic erosion, su ...

line of zero indicates that the

country A country is a distinct part of the world, such as a state, nation, or other political entity. When referring to a specific polity, the term "country" may refer to a sovereign state, state with limited recognition, constituent country, ...

is landlocked.

Overview

The coastline paradox states that a coastline does not have a well-defined length. Measurements of the length of a coastline behave like a

fractal In mathematics, a fractal is a Shape, geometric shape containing detailed structure at arbitrarily small scales, usually having a fractal dimension strictly exceeding the topological dimension. Many fractals appear similar at various scale ...

, being different at different scale intervals (distance between points on the coastline at which measurements are taken). The smaller the scale interval (meaning the more detailed the measurement), the longer the coastline will be. This "magnifying" effect is greater for convoluted coastlines than for relatively smooth ones. * Data marked

The World Factbook ''The World Factbook'', also known as the ''CIA World Factbook'', is a Reference work, reference resource produced by the United States' Central Intelligence Agency (CIA) with almanac-style information about the countries of the world. The off ...

or TWF covers 198 countries and 55 territories, from the book published by the

Central Intelligence Agency The Central Intelligence Agency (CIA; ) is a civilian foreign intelligence service of the federal government of the United States tasked with advancing national security through collecting and analyzing intelligence from around the world and ...

. In addition to coastline lengths, this is the source of the land area used to calculate the "coast/area ratio" for both TWF and WRI (see below) coastline measurement. This ratio measures how many

metre The metre (or meter in US spelling; symbol: m) is the base unit of length in the International System of Units (SI). Since 2019, the metre has been defined as the length of the path travelled by light in vacuum during a time interval of of ...

s of coastline correspond to every square kilometer of land area. The ratio illustrates the ease of accessibility to the country's coast from every point in its interior. Therefore, an

island country An island country, island state, or island nation is a country whose primary territory consists of one or more islands or parts of islands. Approximately 25% of all independent countries are island countries. Island countries are historically ...

Maldives The Maldives, officially the Republic of Maldives, and historically known as the Maldive Islands, is an Archipelagic state, archipelagic country in South Asia located in the Indian Ocean. The Maldives is southwest of Sri Lanka and India, abou ...

, or a country carved by the sea like Greece, is more likely to have a high ratio, while a landlocked country will have a ratio of zero. Note that the scales at which The World Factbook figures were measured are not stated, nor is it known whether the figures are all reported using the same scale, thus the figures are not necessarily comparable across different countries. * Data marked

World Resources Institute The World Resources Institute (WRI) is a global research non-profit organization established in 1982 with funding from the MacArthur Foundation under the leadership of James Gustave Speth. Subsequent presidents include Jonathan Lash (1993– ...

or WRI covers 182 independent countries and 13 dependencies, based on data calculated in 2000 from the World Vector Shoreline, United States Defense Mapping Agency, 1989. It may include territories whose status have changed. According to their technical notes, the "coastline length was derived from the World Vector Shoreline database at 1:250,000 scale. The estimates (...) were calculated using a Geographic Information System (GIS) and an underlying database consistent for the entire world. The methodology used to estimate length is based on the following: 1) A country's coastline is made up of individual lines, and an individual line has two or more vertices and/or nodes. 2) The length between two vertices is calculated on the surface of a sphere. 3) The sum of the lengths of the pairs of vertices is aggregated for each individual line, and 4) the sum of the lengths of individual lines was aggregated for a country. In general, the coastline length of islands that are part of a country, but are not overseas territories, are included in the coastline estimate for that country (e.g., Canary Islands are included in Spain). Coastline length for overseas territories and dependencies are listed separately. Disputed areas are not included in country or regional totals."

List

Data are from the

CIA World Factbook ''The World Factbook'', also known as the ''CIA World Factbook'', is a reference resource produced by the United States' Central Intelligence Agency (CIA) with almanac-style information about the countries of the world. The official print ve ...

and the

. Non-sovereign areas are listed in ''italics''.

Overview

List

See also

Notes

References

Further reading