Lists of ecoregions in the United States
      Lists of ecoregions in the United States — based upon two separate ecoregion classification systems:
-  List of ecoregions in the United States (EPA) — United States Environmental Protection Agency system.
-  List of ecoregions in the United States (WWF) — World Wildlife Fund system.
 
See also
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 |  |  | 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
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 |  |  | Northwestern Forested Mountains |  | 
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 |  |  | Mediterranean California |  | 
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 |  |  | North American Deserts |  | 
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 |  |  | Temperate Sierras |  | 
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 |  |  | Great Plains |  | 
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 |  |  | Eastern Temperate Forest |  | 
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 |  |  | Northern Forests | 
 49 Northern Minnesota Wetlands 50 Northern Lakes and Forests 58 Northeastern Highlands 62 North Central Appalachians
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 |  |  | Tropical Wet Forests | 
 76 Southern Florida Coastal Plain
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 |  |  | Southern Semi-Arid Highlands |  | 
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 |  |  | 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
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 |  |  | Tundra | 
 109 Subarctic Coastal Plains 110 Seward Peninsula 112 Bristol Bay-Nushagak Lowlands 114 Aleutian Islands
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