List of ecoregions in the United States (EPA)

For an alternate classification system, see List of ecoregions in the United States (WWF).

This list of ecoregions in the United States provides an overview of United States ecoregions designated by the U.S. Environmental Protection Agency (EPA) and the Commission for Environmental Cooperation (CEC). The CEC was established in 1994 by the member states of Canada, Mexico, and the United States to address regional environmental concerns under the North American Agreement on Environmental Cooperation (NAAEC), the environmental side accord to the North American Free Trade Agreement (NAFTA). The Commission's 1997 report, Ecological Regions of North America, provides a framework that may be used by government agencies, non-governmental organizations, and academic researchers as a basis for risk analysis, resource management, and environmental study of the continent's ecosystems.^[1] In the United States, the EPA and the United States Geological Survey (USGS) are the principal federal agencies working with the CEC to define and map ecoregions. Ecoregions may be identified by similarities in geology, physiography, vegetation, climate, soils, land use, wildlife distributions, and hydrology.

The classification system has four levels, but only Levels I and III are shown 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.^[2] Level III subdivides the continent into 182 smaller ecoregions; of these, 104 lie partly or wholly with the United States.^[1]^[3] 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 of Hawaii, which is not part of the North American mainland.

Ecoregions in the United States

Level III ecoregions in the contiguous United States. Alaska ecoregions (102-120) not shown.

Marine West Coast Forest

1 Coast Range
2 Puget Lowland
3 Willamette Valley
111 Ahklun Mountains 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.

Western Forested Mountains

The corresponding CEC ecoregion in Canada is called the Montane Cordillera Ecozone.

Mediterranean California

North American Deserts

Temperate Sierras

23 Arizona/New Mexico Mountains

Great Plains

The corresponding name in Canada for the same ecoregion is the Prairies Ecozone.

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.^[4] 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
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 Plateau
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

Tropical and Subtropical coniferous forest

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

Tundra

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

Listings by state

References

1 2 "Ecological Regions of North America: Toward a Common Perspective" (PDF). Commission for Environmental Cooperation. 1997. Retrieved 2008-04-10.
↑ "Western Ecology Division". US EPA. Retrieved 2015-05-31.
↑ "Ecoregion Maps and GIS Resources". United States Environmental Protection Agency. Retrieved 2008-04-10.
↑ Braun, E. L. 1950. The Deciduous Forest of Eastern North America. New York: Hafner.

External links

State maps of US Level III Ecoregions (Select a state. Then select 'Level III Ecoregions')

Level III Ecoregions in the United States

Marine West Coast Forest	1 Coast Range 2 Puget Lowland 3 Willamette Valley 111 Ahklun and Kilbuck Mountains 113 Alaska Peninsula Mountains 115 Cook Inlet 119 Pacific Coastal Mountains 120 Coastal Western Hemlock-Sitka Spruce Forests

Northwestern 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

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 27 Central Great Plains 28 Flint Hills 29 Central Oklahoma/Texas Plains 30 Edwards Plateau 31 Southern Texas Plains 34 Western Gulf Coastal Plain 40 Central Irregular Plains 42 Northwestern Glaciated Plains 43 Northwestern Great Plains 44 Nebraska Sand Hills 45 Piedmont 46 Northern Glaciated Plains 47 Western Corn Belt Plains 48 Lake Agassiz Plain

Eastern Temperate Forest	32 Texas Blackland Prairies 33 East Central Texas Plains 35 South Central Plains 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 59 Northeastern Coastal Zone 60 Northern Appalachian Plateau and Uplands 61 Erie Drift Plain 63 Middle Atlantic Coastal Plain 64 Northern Piedmont 65 Southeastern Plains 66 Blue Ridge 67 Ridge and Valley 68 Southwestern Appalachians 69 Central Appalachians 70 Western Allegheny Plateau 71 Interior Plateau 72 Interior River Valleys and Hills 73 Mississippi Alluvial Plain 74 Mississippi Valley Loess Plains 75 Southern Coastal Plain 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

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

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

as defined by the United States Environmental Protection Agency

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