This list of ecoregions in the United States provides an overview of

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 Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

ecoregions 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 ...

designated by the

U.S. Environmental Protection Agency The Environmental Protection Agency (EPA) is an Independent agencies of the United States government, independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon pro ...

(EPA) and the

Commission for Environmental Cooperation The Commission for Environmental Cooperation (CEC; es, Comisión para la Cooperación Ambiental; french: Commission de coopération environnementale) was established by Canada, Mexico, and the United States to implement the North American Agr ...

(CEC). The CEC was established in 1994 by the member states of

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by to ...

Mexico Mexico (Spanish language, Spanish: México), officially the United Mexican States, is a List of sovereign states, country in the southern portion of North America. It is borders of Mexico, bordered to the north by the United States; to the so ...

, and the

to address regional environmental concerns under the

North American Agreement on Environmental Cooperation The North American Agreement on Environmental Cooperation (NAAEC) is an environmental agreement between the United States of America, Canada and Mexico as a side-treaty of the North American Free Trade Agreement. The agreement came into effect J ...

(NAAEC), the environmental side accord to the

North American Free Trade Agreement The North American Free Trade Agreement (NAFTA ; es, Tratado de Libre Comercio de América del Norte, TLCAN; french: Accord de libre-échange nord-américain, ALÉNA) was an agreement signed by Canada, Mexico, and the United States that crea ...

(NAFTA). The Commission's 1997 report, ''Ecological Regions of North America'', provides a framework that may be used by government agencies,

non-governmental organization A non-governmental organization (NGO) or non-governmental organisation (see spelling differences) is an organization that generally is formed independent from government. They are typically nonprofit entities, and many of them are active in ...

s, and academic researchers as a basis for risk analysis,

resource management In organizational studies, resource management is the efficient and effective development of an organization's resources when they are needed. Such resources may include the financial resources, inventory, human skills, production resources, or ...

, and environmental study of the continent's

ecosystem An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syst ...

s. In the United States, the EPA and the

United States Geological Survey The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...

(USGS) are the principal federal agencies working with the CEC to define and map ecoregions. Ecoregions may be identified by similarities in

geology Geology () is a branch of natural science concerned with Earth and other Astronomical object, astronomical objects, the features or rock (geology), rocks of which it is composed, and the processes by which they change over time. Modern geology ...

physiography Physical geography (also known as physiography) is one of the three main branches of geography. Physical geography is the branch of natural science which deals with the processes and patterns in the natural environment such as the atmosphere, h ...

vegetation Vegetation is an assemblage of plant species and the ground cover they provide. It is a general term, without specific reference to particular taxa, life forms, structure, spatial extent, or any other specific botanical or geographic charac ...

climate Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorologi ...

soil Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former ...

land use Land use involves the management and modification of natural environment or wilderness into built environment such as settlements and semi-natural habitats such as arable fields, pastures, and managed woods. Land use by humans has a long ...

wildlife Wildlife refers to undomesticated animal species, but has come to include all organisms that grow or live wild in an area without being introduced by humans. Wildlife was also synonymous to game: those birds and mammals that were hunted ...

distributions, and

hydrology Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and environmental watershed sustainability. A practitioner of hydrology is call ...

. The classification system has four levels, but only Levels I and III are on this list. Level I divides North America into 15 broad ecoregions; of these, 12 lie partly or wholly within the United States. Fifty Level II regions were created to allow for a narrower delineation of Level I areas. Three level I areas were not subdivided for level 2. Level III subdivides the continent into 182 smaller ecoregions; of these, 104 lie partly or wholly with the United States. Level IV is a further subdivision of Level III ecoregions. Level IV mapping is still underway but is complete across most of the United States. For an example of Level IV data, see List of ecoregions in Oregon and the associated articles. The classification system excludes the

U.S. state In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its sove ...

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...

, which is not part of the North American continent.

Ecoregions in the United States

Marine West Coast Forest

* 1 Coast Range * 2 Puget Lowland * 3 Willamette Valley *111

Ahklun Mountains The Ahklun Mountains are located in the northeast section of the Togiak National Wildlife Refuge in southwest Alaska. They extend southwest from the Kanektok and Narogurum Rivers to Hagemeister Strait and Kuskokwim Bay and support the only exist ...

and Kilbuck Mountains *113 Alaska Peninsula Mountains * 115 Cook Inlet *119 Pacific Coastal Mountains *120 Coastal Western Hemlock-Sitka Spruce Forests The corresponding CEC ecoregion in Canada is called the

Pacific Maritime Ecozone The Pacific Maritime Ecozone, as defined by the Commission for Environmental Cooperation (CEC), is a Canadian terrestrial ecozone, spanning a strip approximately 200 kilometres wide along the British Columbia Coast, then narrowing along the ...

Western Forested Mountains

* 4 Cascades * 5 Sierra Nevada * 9 Eastern Cascades Slopes and Foothills * 11 Blue Mountains * 15 Northern Rockies *16 Idaho Batholith * 17 Middle Rockies * 19 Wasatch and Uinta Mountains * 21 Southern Rockies * 41 Canadian Rockies * 77 North Cascades * 78 Klamath Mountains * 105 Interior Highlands * 116 Alaska Range * 117 Copper Plateau * 118 Wrangell Mountains The corresponding CEC ecoregion in Canada is called the Montane Cordillera Ecozone.

Mediterranean California

* 6 Southern and Central California Chaparral and Oak Woodlands * 7 Central California Valley * 8 Southern California Mountains

North American Deserts

* 10 Columbia Plateau * 12 Snake River Plain * 13 Central Basin and Range * 14 Mojave Basin and Range *18 Wyoming Basin *20 Colorado Plateaus *22 Arizona/New Mexico Plateau * 24 Chihuahuan Deserts * 80 Northern Basin and Range * 81 Sonoran Basin and Range

Temperate Sierras

*23 Arizona/New Mexico Mountains

Great Plains

*25 Western High Plains *26

Southwestern Tablelands The southwestern tablelands comprise an ecoregion running from east-central to south-east Colorado, east-central and a small portion of eastern New Mexico, some eastern portions of the Oklahoma Panhandle, far south-central Kansas, and portions of ...

*27

Central Great Plains The Central Great Plains are a semiarid prairie ecoregion of the central United States, part of North American Great Plains. The region runs from west-central Texas through west-central Oklahoma, central Kansas, and south-central Nebrask ...

* 28 Flint Hills * 29 Central Oklahoma/Texas Plains * 30 Edwards Plateau * 31 Southern Texas Plains *40 Central Irregular Plains *42 Northwestern Glaciated Plains *43 Northwestern

Great Plains The Great Plains (french: Grandes Plaines), sometimes simply "the Plains", is a broad expanse of flatland in North America. It is located west of the Mississippi River and east of the Rocky Mountains, much of it covered in prairie, steppe, a ...

* 44 Nebraska Sand Hills *46

Northern Glaciated Plains The Northern Mixed Grasslands is one of 867 terrestrial ecoregions defined by the World Wide Fund for Nature. This ecoregion includes parts of the Canadian provinces of Alberta, Saskatchewan, and Manitoba, north-central and eastern (except extrem ...

*47

Western Corn Belt Plains The Western Corn Belt Plains is a Level III ecoregion designated by the Environmental Protection Agency (EPA) in seven U.S. states, though predominantly in Iowa. It has been subdivided into fifteen Level IV ecoregions. Description Once covered ...

*48 Lake Agassiz Plain The corresponding name in Canada for the same ecoregion is the

Prairies Ecozone The Prairies Ecozone is a Canadian terrestrial ecozone which spans the southern areas of the Prairie provinces of Alberta, Saskatchewan, and Manitoba. It is a productive agricultural area, and is commonly referred to as "Canada's breadbasket". Fa ...

Eastern Temperate Forest

These forests stretch from the Southern Appalachians towards Canada, up to the northern Midwest. For a general description of these forests, refer to Temperate Deciduous Forest. The standard reference is ''The Deciduous Forest of Eastern North America''.Braun, E. L. 1950. The Deciduous Forest of Eastern North America. New York: Hafner. The adjoining forests in Canada are generally referred to as the Mixedwood Plains Ecozone or the Great Lakes-St.Lawrence Forest Region. * 32 Texas Blackland Prairies * 33 East Central Texas Plains * 34 Western Gulf Coastal Plain * 36 Ouachita Mountains * 37 Arkansas Valley * 38 Boston Mountains * 39 Ozark Highlands * 51 North Central Hardwood Forests * 52 Driftless Area * 53 Southeastern Wisconsin Till Plains * 54 Central Corn Belt Plains * 55 Eastern Corn Belt Plains * 56 Southern Michigan/Northern Indiana Drift Plains * 57 Huron/Erie Lake Plains * 58 Northeastern Highlands * 59 Northeastern Coastal Zone * 60 Northern Appalachian Plateau and Uplands * 61 Erie Drift Plain * 64 Northern Piedmont * 66 Blue Ridge * 67 Ridge and Valley * 68 Southwestern Appalachians * 69 Central Appalachians * 70 Western Allegheny Plateau * 71 Interior Low Plateaus * 72 Interior River Valleys and Hills * 74 Mississippi Valley Loess Plains * 82 Laurentian Plains and Hills * 83 Eastern Great Lakes and Hudson Lowlands * 84 Atlantic Coastal Pine Barrens

Northern Forests

* 49 Northern Minnesota Wetlands * 50 Northern Lakes and Forests * 58 Northeastern Highlands * 62 North Central Appalachians The corresponding name in Canada for the same ecoregions are the Boreal Shield and the Atlantic Maritime Ecozones.

Tropical Wet Forests

* 76 Southern Florida Coastal Plain

Southern Semi-Arid Highlands

* 79 Madrean Archipelago

Taiga

* 101 Arctic Coastal Plain * 102 Arctic Foothills * 103 Brooks Range * 104 Interior Forested Lowlands and Uplands * 106 Interior Bottomlands * 107 Yukon Flats * 108 Ogilvie Mountains

Temperate coniferous forest

* 35 South Central Plains * 45 Piedmont * 63 Middle Atlantic Coastal Plain * 65 Southeastern Plains * 73 Mississippi Alluvial Plain * 74 Mississippi Valley Loess Plains * 75 Southern Coastal Plain

Tundra

* 109 Subarctic Coastal Plains * 110 Seward Peninsula * 112 Bristol Bay-Nushagak Lowlands * 114 Aleutian Islands

Listings by state

* List of ecoregions in Illinois *

List of ecoregions in Indiana The list of ecoregions in Indiana are listings of terrestrial ecoregions (see also, ecosystem) in the United States' State of Indiana, as defined separately by the United States Environmental Protection Agency (USEPA), and the World Wildlife Fu ...

* List of ecoregions in Minnesota * List of ecoregions in Oregon *

List of ecoregions in Wisconsin The list of ecoregions in Wisconsin are listings of terrestrial ecoregions (see also, ecosystem) in the United States' State of Wisconsin, as defined separately by the United States Environmental Protection Agency (USEPA), and the World Wildlife F ...

References

External links

State maps of US Level III Ecoregions
(Select a state. Then select "Level III Ecoregions") {{DEFAULTSORT:Ecoregions In The United States Epa United States EPA EPA United States EPA Natural history of the United States United States EPA Ecoregions, EPA Ecoregions, EPA Ecoregions, EPA