# List of ecoregions in the United States (WWF)

The following is a list of United States ecoregions as identified by the World Wide Fund for Nature (WWF). The United States is a megadiverse country with a high level of endemism across a wide variety of ecosystems.

## Terrestrial ecoregions

The United States is unique among countries in that its terrestrial ecoregions span three biogeographic realms: the Nearctic, Neotropical, and Oceanian realms.

### Fifty states

Alaska is the most biodiverse state with 15 ecoregions across three biomes in the same realm. California comes in a close second with 13 ecoregions across four biomes in the same realm. By contrast, Rhode Island is the least biodiverse with just one ecoregion—the Northeastern coastal forests—encompassing the entire state.
The terrestrial ecoregions of the 50 states of the United States are as follows:
| Realm | Biome | Ecoregion | State |
| Nearctic | Boreal forests/taiga | Alaska Peninsula montane taiga | Alaska |
| Nearctic | Boreal forests/taiga | Cook Inlet taiga | Alaska |
| Nearctic | Boreal forests/taiga | Copper Plateau taiga | Alaska |
| Nearctic | Boreal forests/taiga | Interior Alaska–Yukon lowland taiga | Alaska |
| Nearctic | Deserts and xeric shrublands | Chihuahuan desert | Arizona |
| Nearctic | Deserts and xeric shrublands | Chihuahuan Desert | New Mexico |
| Nearctic | Deserts and xeric shrublands | Chihuahuan Desert | Texas |
| Nearctic | Deserts and xeric shrublands | Colorado Plateau shrublands | Arizona |
| Nearctic | Deserts and xeric shrublands | Colorado Plateau shrublands | Colorado |
| Nearctic | Deserts and xeric shrublands | Colorado Plateau shrublands | New Mexico |
| Nearctic | Deserts and xeric shrublands | Colorado Plateau shrublands | Utah |
| Nearctic | Deserts and xeric shrublands | Great Basin shrub steppe | California |
| Nearctic | Deserts and xeric shrublands | Great Basin shrub steppe | Idaho |
| Nearctic | Deserts and xeric shrublands | Great Basin shrub steppe | Nevada |
| Nearctic | Deserts and xeric shrublands | Great Basin shrub steppe | Utah |
| Nearctic | Deserts and xeric shrublands | Mojave Desert | Arizona |
| Nearctic | Deserts and xeric shrublands | Mojave Desert | California |
| Nearctic | Deserts and xeric shrublands | Mojave Desert | Nevada |
| Nearctic | Deserts and xeric shrublands | Mojave Desert | Utah |
| Nearctic | Deserts and xeric shrublands | Snake-Columbia shrub steppe | California |
| Nearctic | Deserts and xeric shrublands | Snake-Columbia shrub steppe | Idaho |
| Nearctic | Deserts and xeric shrublands | Snake-Columbia shrub steppe | Nevada |
| Nearctic | Deserts and xeric shrublands | Snake-Columbia shrub steppe | Oregon |
| Nearctic | Deserts and xeric shrublands | Snake-Columbia shrub steppe | Washington |
| Nearctic | Deserts and xeric shrublands | Sonoran Desert | Arizona |
| Nearctic | Deserts and xeric shrublands | Sonoran Desert | California |
| Nearctic | Deserts and xeric shrublands | Tamaulipan mezquital | Texas |
| Nearctic | Deserts and xeric shrublands | Wyoming Basin shrub steppe | Colorado |
| Nearctic | Deserts and xeric shrublands | Wyoming Basin shrub steppe | Idaho |
| Nearctic | Deserts and xeric shrublands | Wyoming Basin shrub steppe | Montana |
| Nearctic | Deserts and xeric shrublands | Wyoming Basin shrub steppe | Utah |
| Nearctic | Deserts and xeric shrublands | Wyoming Basin shrub steppe | Wyoming |
| Nearctic | Mediterranean forests, woodlands, and scrub | California coastal sage and chaparral | California |
| Nearctic | Mediterranean forests, woodlands, and scrub | California interior chaparral and woodlands | California |
| Nearctic | Mediterranean forests, woodlands, and scrub | California montane chaparral and woodlands | California |
| Nearctic | Temperate broadleaf and mixed forests | Allegheny Highlands forests | New Jersey |
| Nearctic | Temperate broadleaf and mixed forests | Allegheny Highlands forests | New York |
| Nearctic | Temperate broadleaf and mixed forests | Allegheny Highlands forests | Ohio |
| Nearctic | Temperate broadleaf and mixed forests | Allegheny Highlands forests | Pennsylvania |
| Nearctic | Temperate broadleaf and mixed forests | Appalachian mixed mesophytic forests | Alabama |
| Nearctic | Temperate broadleaf and mixed forests | Appalachian mixed mesophytic forests | Georgia |
| Nearctic | Temperate broadleaf and mixed forests | Appalachian mixed mesophytic forests | Kentucky |
| Nearctic | Temperate broadleaf and mixed forests | Appalachian mixed mesophytic forests | Maryland |
| Nearctic | Temperate broadleaf and mixed forests | Appalachian mixed mesophytic forests | North Carolina |
| Nearctic | Temperate broadleaf and mixed forests | Appalachian mixed mesophytic forests | Ohio |
| Nearctic | Temperate broadleaf and mixed forests | Appalachian mixed mesophytic forests | Pennsylvania |
| Nearctic | Temperate broadleaf and mixed forests | Appalachian mixed mesophytic forests | Tennessee |
| Nearctic | Temperate broadleaf and mixed forests | Appalachian mixed mesophytic forests | Virginia |
| Nearctic | Temperate broadleaf and mixed forests | Appalachian mixed mesophytic forests | West Virginia |
| Nearctic | Temperate broadleaf and mixed forests | Appalachian–Blue Ridge forests | Alabama |
| Nearctic | Temperate broadleaf and mixed forests | Appalachian–Blue Ridge forests | Georgia |
| Nearctic | Temperate broadleaf and mixed forests | Appalachian–Blue Ridge forests | Maryland |
| Nearctic | Temperate broadleaf and mixed forests | Appalachian–Blue Ridge forests | New Jersey |
| Nearctic | Temperate broadleaf and mixed forests | Appalachian–Blue Ridge forests | New York |
| Nearctic | Temperate broadleaf and mixed forests | Appalachian–Blue Ridge forests | North Carolina |
| Nearctic | Temperate broadleaf and mixed forests | Appalachian–Blue Ridge forests | Pennsylvania |
| Nearctic | Temperate broadleaf and mixed forests | Appalachian–Blue Ridge forests | South Carolina |
| Nearctic | Temperate broadleaf and mixed forests | Appalachian–Blue Ridge forests | Tennessee |
| Nearctic | Temperate broadleaf and mixed forests | Appalachian–Blue Ridge forests | Virginia |
| Nearctic | Temperate broadleaf and mixed forests | Appalachian–Blue Ridge forests | West Virginia |
| Nearctic | Temperate broadleaf and mixed forests | Central U.S. hardwood forests | Alabama |
| Nearctic | Temperate broadleaf and mixed forests | Central U.S. hardwood forests | Arkansas |
| Nearctic | Temperate broadleaf and mixed forests | Central U.S. hardwood forests | Illinois |
| Nearctic | Temperate broadleaf and mixed forests | Central U.S. hardwood forests | Indiana |
| Nearctic | Temperate broadleaf and mixed forests | Central U.S. hardwood forests | Kentucky |
| Nearctic | Temperate broadleaf and mixed forests | Central U.S. hardwood forests | Mississippi |
| Nearctic | Temperate broadleaf and mixed forests | Central U.S. hardwood forests | Missouri |
| Nearctic | Temperate broadleaf and mixed forests | Central U.S. hardwood forests | Ohio |
| Nearctic | Temperate broadleaf and mixed forests | Central U.S. hardwood forests | Oklahoma |
| Nearctic | Temperate broadleaf and mixed forests | Central U.S. hardwood forests | Tennessee |
| Nearctic | Temperate broadleaf and mixed forests | East Central Texas forests | Texas |
| Nearctic | Temperate broadleaf and mixed forests | Eastern Great Lakes lowland forests | New York |
| Nearctic | Temperate broadleaf and mixed forests | Eastern Great Lakes lowland forests | Vermont |
| Nearctic | Temperate broadleaf and mixed forests | Eastern forest–boreal transition | New York |
| Nearctic | Temperate broadleaf and mixed forests | Mississippi lowland forests | Arkansas |
| Nearctic | Temperate broadleaf and mixed forests | Mississippi lowland forests | Illinois |
| Nearctic | Temperate broadleaf and mixed forests | Mississippi lowland forests | Kentucky |
| Nearctic | Temperate broadleaf and mixed forests | Mississippi lowland forests | Louisiana |
| Nearctic | Temperate broadleaf and mixed forests | Mississippi lowland forests | Mississippi |
| Nearctic | Temperate broadleaf and mixed forests | Mississippi lowland forests | Missouri |
| Nearctic | Temperate broadleaf and mixed forests | Mississippi lowland forests | Tennessee |
| Nearctic | Temperate broadleaf and mixed forests | New England–Acadian forests | Connecticut |
| Nearctic | Temperate broadleaf and mixed forests | New England–Acadian forests | Maine |
| Nearctic | Temperate broadleaf and mixed forests | New England–Acadian forests | Massachusetts |
| Nearctic | Temperate broadleaf and mixed forests | New England–Acadian forests | New Hampshire |
| Nearctic | Temperate broadleaf and mixed forests | New England–Acadian forests | New York |
| Nearctic | Temperate broadleaf and mixed forests | New England–Acadian forests | Vermont |
| Nearctic | Temperate broadleaf and mixed forests | Northeastern coastal forests | Connecticut |
| Nearctic | Temperate broadleaf and mixed forests | Northeastern coastal forests | Delaware |
| Nearctic | Temperate broadleaf and mixed forests | Northeastern coastal forests | Maine |
| Nearctic | Temperate broadleaf and mixed forests | Northeastern coastal forests | Maryland |
| Nearctic | Temperate broadleaf and mixed forests | Northeastern coastal forests | Massachusetts |
| Nearctic | Temperate broadleaf and mixed forests | Northeastern coastal forests | New Hampshire |
| Nearctic | Temperate broadleaf and mixed forests | Northeastern coastal forests | New Jersey |
| Nearctic | Temperate broadleaf and mixed forests | Northeastern coastal forests | New York |
| Nearctic | Temperate broadleaf and mixed forests | Northeastern coastal forests | Pennsylvania |
| Nearctic | Temperate broadleaf and mixed forests | Northeastern coastal forests | Rhode Island |
| Nearctic | Temperate broadleaf and mixed forests | Northeastern coastal forests | Vermont |
| Nearctic | Temperate broadleaf and mixed forests | Ozark Mountain forests | Arkansas |
| Nearctic | Temperate broadleaf and mixed forests | Ozark Mountain forests | Oklahoma |
| Nearctic | Temperate broadleaf and mixed forests | Southeastern mixed forests | Alabama |
| Nearctic | Temperate broadleaf and mixed forests | Southeastern mixed forests | Georgia |
| Nearctic | Temperate broadleaf and mixed forests | Southeastern mixed forests | Louisiana |
| Nearctic | Temperate broadleaf and mixed forests | Southeastern mixed forests | Maryland |
| Nearctic | Temperate broadleaf and mixed forests | Southeastern mixed forests | Mississippi |
| Nearctic | Temperate broadleaf and mixed forests | Southeastern mixed forests | North Carolina |
| Nearctic | Temperate broadleaf and mixed forests | Southeastern mixed forests | Pennsylvania |
| Nearctic | Temperate broadleaf and mixed forests | Southeastern mixed forests | South Carolina |
| Nearctic | Temperate broadleaf and mixed forests | Southeastern mixed forests | Tennessee |
| Nearctic | Temperate broadleaf and mixed forests | Southeastern mixed forests | Virginia |
| Nearctic | Temperate broadleaf and mixed forests | Southern Great Lakes forests | Indiana |
| Nearctic | Temperate broadleaf and mixed forests | Southern Great Lakes forests | Michigan |
| Nearctic | Temperate broadleaf and mixed forests | Southern Great Lakes forests | New York |
| Nearctic | Temperate broadleaf and mixed forests | Southern Great Lakes forests | Ohio |
| Nearctic | Temperate broadleaf and mixed forests | Southern Great Lakes forests | Pennsylvania |
| Nearctic | Temperate broadleaf and mixed forests | Upper Midwest forest–savanna transition | Illinois |
| Nearctic | Temperate broadleaf and mixed forests | Upper Midwest forest–savanna transition | Iowa |
| Nearctic | Temperate broadleaf and mixed forests | Upper Midwest forest–savanna transition | Michigan |
| Nearctic | Temperate broadleaf and mixed forests | Upper Midwest forest–savanna transition | Minnesota |
| Nearctic | Temperate broadleaf and mixed forests | Upper Midwest forest–savanna transition | Wisconsin |
| Nearctic | Temperate broadleaf and mixed forests | Western Great Lakes forests | Michigan |
| Nearctic | Temperate broadleaf and mixed forests | Western Great Lakes forests | Minnesota |
| Nearctic | Temperate broadleaf and mixed forests | Western Great Lakes forests | Wisconsin |
| Nearctic | Temperate broadleaf and mixed forests | Willamette Valley forests | Oregon |
| Nearctic | Temperate broadleaf and mixed forests | Willamette Valley forests | Washington |
| Nearctic | Temperate coniferous forests | Arizona Mountains forests | Arizona |
| Nearctic | Temperate coniferous forests | Arizona Mountains forests | New Mexico |
| Nearctic | Temperate coniferous forests | Arizona Mountains forests | Texas |
| Nearctic | Temperate coniferous forests | Atlantic coastal pine barrens | Massachusetts |
| Nearctic | Temperate coniferous forests | Atlantic coastal pine barrens | New Jersey |
| Nearctic | Temperate coniferous forests | Atlantic coastal pine barrens | New York |
| Nearctic | Temperate coniferous forests | Blue Mountains forests | Idaho |
| Nearctic | Temperate coniferous forests Deserts and xeric shrublands | Blue Mountains | Oregon |
| Nearctic | Temperate coniferous forests | Blue Mountains forests | Washington |
| Nearctic | Temperate coniferous forests | British Columbia mainland coastal forests | Washington |
| Nearctic | Temperate coniferous forests | Cascade Mountains leeward forests | Washington |
| Nearctic | Temperate coniferous forests | Central Pacific coastal forests | Oregon |
| Nearctic | Temperate coniferous forests | Central Pacific coastal forests | Washington |
| Nearctic | Temperate coniferous forests | Central and Southern Cascades forests | Oregon |
| Nearctic | Temperate coniferous forests | Central and Southern Cascades forests | Washington |
| Nearctic | Temperate coniferous forests | Colorado Rockies forests | Colorado |
| Nearctic | Temperate coniferous forests | Colorado Rockies forests | New Mexico |
| Nearctic | Temperate coniferous forests | Colorado Rockies forests | Wyoming |
| Nearctic | Temperate coniferous forests Desert and xeric shrubland | Eastern Cascades forests | California |
| Nearctic | Temperate coniferous forests | Eastern Cascades forests | Oregon |
| Nearctic | Temperate coniferous forests | Eastern Cascades forests | Washington |
| Nearctic | Temperate coniferous forests | Florida sand pine scrub | Florida |
| Nearctic | Temperate coniferous forests | Great Basin montane forests | California |
| Nearctic | Temperate coniferous forests | Great Basin montane forests | Nevada |
| Nearctic | Temperate coniferous forests | Great Basin montane forests | Oregon |
| Nearctic | Temperate coniferous forests | Klamath–Siskiyou forests | California |
| Nearctic | Temperate coniferous forests | Klamath–Siskiyou forests | Oregon |
| Nearctic | Temperate coniferous forests | Middle Atlantic coastal forests | Delaware |
| Nearctic | Temperate coniferous forests | Middle Atlantic coastal forests | Georgia |
| Nearctic | Temperate coniferous forests | Middle Atlantic coastal forests | Maryland |
| Nearctic | Temperate coniferous forests | Middle Atlantic coastal forests | North Carolina |
| Nearctic | Temperate coniferous forests | Middle Atlantic coastal forests | South Carolina |
| Nearctic | Temperate coniferous forests | Middle Atlantic coastal forests | Virginia |
| Nearctic | Temperate coniferous forests | North Central Rockies forests | Idaho |
| Nearctic | Temperate coniferous forests | North Central Rockies forests | Montana |
| Nearctic | Temperate coniferous forests | North Central Rockies forests | Washington |
| Nearctic | Temperate coniferous forests | Northern California coastal forests | California |
| Nearctic | Temperate coniferous forests | Northern California coastal forests | Oregon |
| Nearctic | Temperate coniferous forests | Northern Pacific coastal forests | Alaska |
| Nearctic | Temperate coniferous forests | Okanagan dry forests | Washington |
| Nearctic | Temperate coniferous forests | Piney Woods forests | Arkansas |
| Nearctic | Temperate coniferous forests | Piney Woods forests | Louisiana |
| Nearctic | Temperate coniferous forests | Piney Woods forests | Oklahoma |
| Nearctic | Temperate coniferous forests | Piney Woods forests | Texas |
| Nearctic | Temperate coniferous forests | Puget lowland forests | Washington |
| Nearctic | Temperate coniferous forests | Sierra Nevada forests | California |
| Nearctic | Temperate coniferous forests | Sierra Nevada forests | Nevada |
| Nearctic | Temperate coniferous forests | South Central Rockies forests | Idaho |
| Nearctic | Temperate coniferous forests | South Central Rockies forests | Montana |
| Nearctic | Temperate coniferous forests | South Central Rockies forests | South Dakota |
| Nearctic | Temperate coniferous forests | South Central Rockies forests | Wyoming |
| Nearctic | Temperate coniferous forests | Southeastern conifer forests | Alabama |
| Nearctic | Temperate coniferous forests | Southeastern conifer forests | Florida |
| Nearctic | Temperate coniferous forests | Southeastern conifer forests | Georgia |
| Nearctic | Temperate coniferous forests | Southeastern conifer forests | Louisiana |
| Nearctic | Temperate coniferous forests | Southeastern conifer forests | Mississippi |
| Nearctic | Temperate coniferous forests | Wasatch and Uinta montane forests | Idaho |
| Nearctic | Temperate coniferous forests | Wasatch and Uinta montane forests | Utah |
| Nearctic | Temperate coniferous forests | Wasatch and Uinta montane forests | Wyoming |
| Nearctic | Temperate grasslands, savannas, and shrublands | California Central Valley grasslands | California |
| Nearctic | Temperate grasslands, savannas, and shrublands | Canadian aspen forests and parklands | Minnesota |
| Nearctic | Temperate grasslands, savannas, and shrublands | Canadian aspen forests and parklands | North Dakota |
| Nearctic | Temperate grasslands, savannas, and shrublands | Central and Southern mixed grasslands | Kansas |
| Nearctic | Temperate grasslands, savannas, and shrublands | Central and Southern mixed grasslands | Nebraska |
| Nearctic | Temperate grasslands, savannas, and shrublands | Central and Southern mixed grasslands | Oklahoma |
| Nearctic | Temperate grasslands, savannas, and shrublands | Central and Southern mixed grasslands | Texas |
| Nearctic | Temperate grasslands, savannas, and shrublands | Central forest–grasslands transition | Illinois |
| Nearctic | Temperate grasslands, savannas, and shrublands | Central forest–grasslands transition | Indiana |
| Nearctic | Temperate grasslands, savannas, and shrublands | Central forest–grasslands transition | Iowa |
| Nearctic | Temperate grasslands, savannas, and shrublands | Central forest–grasslands transition | Kansas |
| Nearctic | Temperate grasslands, savannas, and shrublands | Central forest–grasslands transition | Missouri |
| Nearctic | Temperate grasslands, savannas, and shrublands | Central forest–grasslands transition | Oklahoma |
| Nearctic | Temperate grasslands, savannas, and shrublands | Central forest–grasslands transition | Texas |
| Nearctic | Temperate grasslands, savannas, and shrublands | Central forest–grasslands transition | Wisconsin |
| Nearctic | Temperate grasslands, savannas, and shrublands | Central tall grasslands | Iowa |
| Nearctic | Temperate grasslands, savannas, and shrublands | Central tall grasslands | Kansas |
| Nearctic | Temperate grasslands, savannas, and shrublands | Central tall grasslands | Minnesota |
| Nearctic | Temperate grasslands, savannas, and shrublands | Central tall grasslands | Missouri |
| Nearctic | Temperate grasslands, savannas, and shrublands | Central tall grasslands | Nebraska |
| Nearctic | Temperate grasslands, savannas, and shrublands | Central tall grasslands | North Dakota |
| Nearctic | Temperate grasslands, savannas, and shrublands | Central tall grasslands | South Dakota |
| Nearctic | Temperate grasslands, savannas, and shrublands | Central tall grasslands | Wisconsin |
| Nearctic | Temperate grasslands, savannas, and shrublands | Edwards Plateau savanna | Texas |
| Nearctic | Temperate grasslands, savannas, and shrublands | Flint Hills tall grasslands | Kansas |
| Nearctic | Temperate grasslands, savannas, and shrublands | Flint Hills tall grasslands | Oklahoma |
| Nearctic | Temperate grasslands, savannas, and shrublands | Montana valley and foothill grasslands | Montana |
| Nearctic | Temperate grasslands, savannas, and shrublands | Nebraska Sand Hills mixed grasslands | Nebraska |
| Nearctic | Temperate grasslands, savannas, and shrublands | Nebraska Sand Hills mixed grasslands | South Dakota |
| Nearctic | Temperate grasslands, savannas, and shrublands | Northern mixed grasslands | Nebraska |
| Nearctic | Temperate grasslands, savannas, and shrublands | Northern mixed grasslands | North Dakota |
| Nearctic | Temperate grasslands, savannas, and shrublands | Northern mixed grasslands | South Dakota |
| Nearctic | Temperate grasslands, savannas, and shrublands | Northern short grasslands | Montana |
| Nearctic | Temperate grasslands, savannas, and shrublands | Northern short grasslands | Nebraska |
| Nearctic | Temperate grasslands, savannas, and shrublands | Northern short grasslands | North Dakota |
| Nearctic | Temperate grasslands, savannas, and shrublands | Northern short grasslands | South Dakota |
| Nearctic | Temperate grasslands, savannas, and shrublands | Northern short grasslands | Wyoming |
| Nearctic | Temperate grasslands, savannas, and shrublands | Northern tall grasslands | Minnesota |
| Nearctic | Temperate grasslands, savannas, and shrublands | Northern tall grasslands | North Dakota |
| Nearctic | Temperate grasslands, savannas, and shrublands | Northern tall grasslands | South Dakota |
| Nearctic | Temperate grasslands, savannas, and shrublands | Palouse grasslands | Idaho |
| Nearctic | Temperate grasslands, savannas, and shrublands | Palouse grasslands | Oregon |
| Nearctic | Temperate grasslands, savannas, and shrublands | Palouse grasslands | Washington |
| Nearctic | Temperate grasslands, savannas, and shrublands | Texas blackland prairies | Texas |
| Nearctic | Temperate grasslands, savannas, and shrublands | Western short grasslands | Colorado |
| Nearctic | Temperate grasslands, savannas, and shrublands | Western short grasslands | Kansas |
| Nearctic | Temperate grasslands, savannas, and shrublands | Western short grasslands | Nebraska |
| Nearctic | Temperate grasslands, savannas, and shrublands | Western short grasslands | New Mexico |
| Nearctic | Temperate grasslands, savannas, and shrublands | Western short grasslands | Oklahoma |
| Nearctic | Temperate grasslands, savannas, and shrublands | Western short grasslands | South Dakota |
| Nearctic | Temperate grasslands, savannas, and shrublands | Western short grasslands | Texas |
| Nearctic | Temperate grasslands, savannas, and shrublands | Western short grasslands | Wyoming |
| Nearctic | Tropical and subtropical coniferous forests | Sierra Madre Occidental pine–oak forests | Arizona |
| Nearctic | Tropical and subtropical coniferous forests | Sierra Madre Occidental pine–oak forests | New Mexico |
| Nearctic | Tropical and subtropical coniferous forests | Sierra Madre Oriental pine–oak forests | Texas |
| Nearctic | Tropical and subtropical grasslands, savannas, and shrublands | Western Gulf coastal grasslands | Louisiana |
| Nearctic | Tropical and subtropical grasslands, savannas, and shrublands | Western Gulf coastal grasslands | Mississippi |
| Nearctic | Tropical and subtropical grasslands, savannas, and shrublands | Western Gulf coastal grasslands | Texas |
| Nearctic | Tundra | Alaska–St. Elias Range tundra | Alaska |
| Nearctic | Tundra | Aleutian Islands tundra | Alaska |
| Nearctic | Tundra | Arctic coastal tundra | Alaska |
| Nearctic | Tundra | Arctic foothills tundra | Alaska |
| Nearctic | Tundra | Beringia lowland tundra | Alaska |
| Nearctic | Tundra | Beringia upland tundra | Alaska |
| Nearctic | Tundra | Brooks–British Range tundra | Alaska |
| Nearctic | Tundra | Interior Yukon–Alaska alpine tundra | Alaska |
| Nearctic | Tundra | Ogilvie–MacKenzie alpine tundra | Alaska |
| Nearctic | Tundra | Pacific Coastal Mountain icefields and tundra | Alaska |
| Neotropical | Flooded grasslands and savannas | Everglades | Florida |
| Neotropical | Tropical and subtropical moist broadleaf forests | South Florida rocklands | Florida |
| Oceanian | Tropical and subtropical dry broadleaf forests | Hawaiian tropical dry forests | Hawaii |
| Oceanian | Tropical and subtropical grasslands, savannas, and shrublands | Hawaiian tropical high shrublands | Hawaii |
| Oceanian | Tropical and subtropical grasslands, savannas, and shrublands | Hawaiian tropical low shrublands | Hawaii |
| Oceanian | Tropical and subtropical grasslands, savannas, and shrublands | Northwestern Hawaii scrub | Hawaii |
| Oceanian | Tropical and subtropical moist broadleaf forests | Hawaiian tropical rainforests | Hawaii |

### Five inhabited territories

The ecoregions of the 5 inhabited territories of the United States are as follows:
| Realm | Biome | Ecoregion | Territory |
| Neotropical | Deserts and xeric shrublands | Leeward Islands xeric scrub | U.S. Virgin Islands |
| Neotropical | Mangroves | Greater Antilles mangroves | Puerto Rico |
| Neotropical | Mangroves | Greater Antilles mangroves | U.S. Virgin Islands |
| Neotropical | Tropical and subtropical dry broadleaf forests | Puerto Rican dry forests | Puerto Rico |
| Neotropical | Tropical and subtropical moist broadleaf forests | Leeward Islands moist forests | U.S. Virgin Islands |
| Neotropical | Tropical and subtropical moist broadleaf forests | Puerto Rican moist forests | Puerto Rico |
| Oceanian | Tropical and subtropical dry broadleaf forests | Marianas tropical dry forests | Guam |
| Oceanian | Tropical and subtropical dry broadleaf forests | Marianas tropical dry forests | Northern Mariana Islands |
| Oceanian | Tropical and subtropical moist broadleaf forests | Samoan tropical moist forests | American Samoa |

## Marine ecoregions

The marine ecoregions of the 50 states of the United States are as follows:
| Realm | Biome | Ecoregion | State |
| Arctic | Arctic | Beaufort Sea continental coast and shelf | Alaska |
| Arctic | Arctic | Chukchi Sea | Alaska |
| Arctic | Arctic | Eastern Bering Sea | Alaska |
| Eastern Indo-Pacific | Tropical Mid-Pacific (Hawaii) | Hawaiian Islands | Hawaii |
| Temperate Northern Atlantic | Cold Temperate Northwest Atlantic | Gulf of Maine-Bay of Fundy | Maine |
| Temperate Northern Atlantic | Cold Temperate Northwest Atlantic | Gulf of Maine-Bay of Fundy | Massachusetts |
| Temperate Northern Atlantic | Cold Temperate Northwest Atlantic | Gulf of Maine-Bay of Fundy | New Hampshire |
| Temperate Northern Atlantic | Cold Temperate Northwest Atlantic | Virginian | Connecticut |
| Temperate Northern Atlantic | Cold Temperate Northwest Atlantic | Virginian | Delaware |
| Temperate Northern Atlantic | Cold Temperate Northwest Atlantic | Virginian | Maryland |
| Temperate Northern Atlantic | Cold Temperate Northwest Atlantic | Virginian | Massachusetts |
| Temperate Northern Atlantic | Cold Temperate Northwest Atlantic | Virginian | New Jersey |
| Temperate Northern Atlantic | Cold Temperate Northwest Atlantic | Virginian | New York |
| Temperate Northern Atlantic | Cold Temperate Northwest Atlantic | Virginian | North Carolina |
| Temperate Northern Atlantic | Cold Temperate Northwest Atlantic | Virginian | Pennsylvania |
| Temperate Northern Atlantic | Cold Temperate Northwest Atlantic | Virginian | Rhode Island |
| Temperate Northern Atlantic | Cold Temperate Northwest Atlantic | Virginian | Virginia |
| Temperate Northern Atlantic | Warm Temperate Northwest Atlantic | Carolinian | Florida |
| Temperate Northern Atlantic | Warm Temperate Northwest Atlantic | Carolinian | Georgia |
| Temperate Northern Atlantic | Warm Temperate Northwest Atlantic | Carolinian | North Carolina |
| Temperate Northern Atlantic | Warm Temperate Northwest Atlantic | Carolinian | South Carolina |
| Temperate Northern Atlantic | Warm Temperate Northwest Atlantic | Northern Gulf of Mexico | Alabama |
| Temperate Northern Atlantic | Warm Temperate Northwest Atlantic | Northern Gulf of Mexico | Florida |
| Temperate Northern Atlantic | Warm Temperate Northwest Atlantic | Northern Gulf of Mexico | Louisiana |
| Temperate Northern Atlantic | Warm Temperate Northwest Atlantic | Northern Gulf of Mexico | Mississippi |
| Temperate Northern Atlantic | Warm Temperate Northwest Atlantic | Northern Gulf of Mexico | Texas |
| Temperate Northern Pacific | Cold Temperate Northeast Pacific | Aleutian Islands | Alaska |
| Temperate Northern Pacific | Cold Temperate Northeast Pacific | Gulf of Alaska | Alaska |
| Temperate Northern Pacific | Cold Temperate Northeast Pacific | North American Pacific Fjordland | Alaska |
| Temperate Northern Pacific | Cold Temperate Northeast Pacific | Northern California | California |
| Temperate Northern Pacific | Cold Temperate Northeast Pacific | Oregon, Washington, Vancouver coast and shelf | California |
| Temperate Northern Pacific | Cold Temperate Northeast Pacific | Oregon, Washington, Vancouver coast and shelf | Oregon |
| Temperate Northern Pacific | Cold Temperate Northeast Pacific | Oregon, Washington, Vancouver coast and shelf | Washington |
| Temperate Northern Pacific | Cold Temperate Northeast Pacific | Puget Trough/Georgia Basin | Washington |
| Temperate Northern Pacific | Warm Temperate Northeast Pacific | Southern California Bight | California |
| Tropical Atlantic | Tropical Northwestern Atlantic | Floridian | Florida |