The following is a list of

ecoregion An ecoregion (ecological region) or ecozone (ecological zone) is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than a biogeographic realm. Ecoregions cover relatively large areas of l ...

s in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

as identified by the

World Wide Fund for Nature The World Wide Fund for Nature Inc. (WWF) is an international non-governmental organization founded in 1961 that works in the field of wilderness preservation and the reduction of human impact on the environment. It was formerly named the Wor ...

(WWF). The United States is a megadiverse country with a high level of

endemism Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

across a wide variety of ecosystems.

Terrestrial ecoregions

The United States is unique among countries in that its

terrestrial ecoregions An ecoregion (ecological region) or ecozone (ecological zone) is an ecology, ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than a biogeographic realm. Ecoregions cover relatively large a ...

span three

biogeographic realm A biogeographic realm or ecozone is the broadest biogeographic division of Earth's land surface, based on distributional patterns of terrestrial organisms. They are subdivided into bioregions, which are further subdivided into ecoregions. De ...

s: the

Nearctic The Nearctic realm is one of the eight biogeographic realms constituting the Earth's land surface. The Nearctic realm covers most of North America, including Greenland, Central Florida, and the highlands of Mexico. The parts of North America t ...

Neotropical The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropical terrestrial ecoregions of the Americas and the entire South American temperate zone. Definition In bioge ...

, and

Oceanian realm The Oceanian realm is one of the World Wildlife Fund (WWF) biogeographic realms, and is unique in not including any continental land mass. It has the smallest land area of any of the WWF realms. This realm includes the islands of the Pacific Oc ...

50 states

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...

is the most

biodiverse Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic ('' genetic variability''), species ('' species diversity''), and ecosystem ('' ecosystem diversity'') ...

state with 15 ecoregions across 3

biome A biome () is a biogeographical unit consisting of a biological community that has formed in response to the physical environment in which they are found and a shared regional climate. Biomes may span more than one continent. Biome is a broader ...

s in the same

realm A realm is a community or territory over which a sovereign rules. The term is commonly used to describe a monarchical or dynastic state. A realm may also be a subdivision within an empire, if it has its own monarch, e.g. the German Empire. Etym ...

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

comes in a close second with 13 ecoregions across 4 biomes in the same realm. By contrast,

Rhode Island Rhode Island (, like ''road'') is a U.S. state, state in the New England region of the Northeastern United States. It is the List of U.S. states by area, smallest U.S. state by area and the List of states and territories of the United States ...

is the least biodiverse with just one ecoregion - the

Northeastern coastal forests The Northeastern coastal forests are a temperate broadleaf and mixed forests ecoregion of the northeast and middle Atlantic region of the United States. The ecoregion covers an area of 34,630 sq miles (89,691 km2) encompassing the Piedmont a ...

- encompassing the entire state. The terrestrial ecoregions of the

50 states The United States of America is a federal republic consisting of 50 states, a federal district (Washington, D.C., the capital city of the United States), five major territories, and various minor islands. Both the states and the United S ...

of the United States are as follows:

5 inhabited territories

The ecoregions of the 5 inhabited territories of the United States are as follows:

Marine ecoregions

The marine ecoregions of the

of the United States are as follows:

References

* Ricketts, Taylor H; Eric Dinerstein; David M. Olson; Colby J. Loucks; et al. (1999). ''Terrestrial Ecoregions of North America: a Conservation Assessment.'' Island Press;

Washington, DC ) , image_skyline = , image_caption = Clockwise from top left: the Washington Monument and Lincoln Memorial on the National Mall, United States Capitol, Logan Circle, Jefferson Memorial, White House, Adams Morgan ...

. {{Ecoregions in the United States WWF United States, WWF Ecoregions, WWF Ecoregions, WWF Natural history of the United States Ecoregions WWF United States WWF United States WWF

Terrestrial ecoregions

50 states

5 inhabited territories

Marine ecoregions

See also

References