One Earth utilizes these 14 realm divisions – further divided into 52 subrealms, 185 bioregions, and 844 ecoregions – as a framework to better understand the natural world that surrounds us.

Adriatic Sea & Central Mediterranean Mixed Forests (PA19)

Aegean Sea & East Mediterranean Mixed Forests (PA18)

Afghan-Balochistan Drylands, Mountain Meadows & Conifer Forests (PA30)

Alps & Po Basin Mixed Forests (PA13)

Altai Mountain Forests, Grasslands & Desert Steppe (PA37)

Amazon River Estuary (NT16)

Amsterdam-Saint Paul Islands (AT3)

Andean Mountain Forests & Valleys (NT11)

Andean Mountain Grasslands (NT5)

Antarctic Peninsula & Scotia Sea (AN2)

Appalachia & Allegheny Interior Forests (NA24)

Arakan Mountains & Northern Triangle Forests (IM10)

Azores Forest Islands (PA21)

Baja California & Southern Deserts (NA30)

Balearic Sea & West Mediterranean Mixed Forests (PA20)

Baltic Sea & Sarmatic Mixed Forests (PA11)

Bermuda (NA26)

Black Sea, Caucasus-Anatolian Mixed Forests & Steppe (PA17)

Borneo Tropical Forests & Sundaland Heath Forests (IM16)

Brazilian Atlantic Dry Forests (NT15)

Brazilian Atlantic Moist Forests (NT14)

Canadian Shield & Coastal Taiga-Forests (NA9)

Canadian Tundra (NA2)

Cape Verde Islands (AT24)

Caribbean Islands (NT26)

Carpathian Mountain & Plains Mixed Forests (PA14)

Cascades Mountain Forests & Valleys (NA16)

Caspian Sea, Coastal Deserts & Kopet Dagh Mountain Woodlands (PA33)

Central Amazonian Forests (NT19)

Central American Isthmian & Colombian Coastal Forests (NT24)

Central American Mixed Forests (NT25)

Central Asian Deserts & Riparian Woodlands (PA32)

Central Congolian Tropical Forests (AT14)

Central Indian Ocean Islands (IM1)

Central Polynesian Islands (OC4)

Cerrado Savannas (NT13)

Chaco Grasslands (NT4)

Chang Jiang Plain Evergreen Forests (PA50)

Chilean Matorral Shrublands & Savanna (NT6)

Chilean Mixed Forests (NT1)

Colorado Plateau & Mountain Forests (NA19)

Columbia Plateau & Blue Mountains (NA17)

Continental Antarctica (AN1)

Coral Sea & New Caledonia Islands (AU10)

Dinaric Mountains & Balkan Mixed Forests (PA15)

Dzhagdy Mountain Conifer Forests (PA45)

East African Coastal Forests (AT7)

East Australian Mediterranean Woodlands & Temperate Savannas (AU4)

East Australian Temperate Forests & Mountain Shrublands (AU3)

East Eurasian Coastal Tundra (PA5)

East Micronesian Islands (OC7)

Ecuadorean Dry Coastal Forests & Flooded Grasslands (NT10)

European Interior Mixed Forests (PA12)

Far Northern Pacific Coast (NA5)

Fiji & Tongan Tropical Islands (OC6)

Galápagos Islands (NT9)

Great Basin & Columbia Steppe (NA18)

Great Britain, Ireland & Faroe Islands (PA9)

Greater African Subequatorial Savannas & Mixed Woodlands (AT11)

Greater Alaska Taiga & Tundra (NA4)

Greater Australian Interior Desert & Shrublands (AU7)

Greater California (NA31)

Greater Deccan-Sri Lankan Forests & Drylands (IM8)

Greater Eurasian Tundra (PA4)

Greater Gobi Desert (PA43)

Greater Karoo & Kalahari Drylands (AT9)

Greater Rockies & Mountain Forests (NA13)

Greater Tibetan Plateau Alpine Meadows & Shrublands (PA40)

Greater Yukon (NA6)

Greenland (NA1)

Guam & Marianas Dry Tropical Islands (OC9)

Guianan Forests & Savanna (NT21)

Guizhou & Yunnan Subtropical Forest Plateaus (PA52)

Gulf of Guinea Coastal Forests & Mangroves (AT17)

Hawai’i Tropical Islands (OC11)

Hengduan Mountain Conifer Forests (PA53)

Himalayan Mixed Forests & Grasslands (IM5)

Iceland (PA2)

Indian Dry Deciduous Forests (IM3)

Indian Tropical Coastal Forests (IM2)

Indochina Mixed Forests & Peatlands (IM12)

Interior Plateau & Southern Great Lakes Forests (NA23)

Irrawaddy & North Indochina Mixed Forests (IM11)

Japan Forest Islands (PA47)

Javan-Bali Tropical Rainforests (IM17)

Juan Fernández & Desventuradas Islands (NT7)

Junggar Semi-Desert & Ermin Valley Steppe (PA38)

Kazakh Forest Steppe & Grasslands (PA34)

Korean Peninsula Mixed Forests (PA48)

Lake Turkana-Sudd Grasslands, Bushlands & Forests (AT21)

Llanos & Dry Forests (NT22)

Loess Plateau & Huang He Plain Mixed Forests (PA49)

Lord Howe & Norfolk Islands (AU2)

Madagascar Island (AT6)

Madeira Evergreen Island (PA22)

Manchuria-Ussuri Mixed Forests & Meadow Steppes (PA46)

Mandara Mountain & North Congolian Forest-Savannas (AT16)

Marquesas Tropical Islands (OC2)

Mascarene Tropical Forest Islands (AT4)

Mexican Dry & Coniferous Forests (NT28)

Mexican Subtropical Islands (NT29)

Mid-Canada Boreal Plains & Foothill Forests (NA8)

Midwestern Tallgrass Prairie & Forest Transition (NA21)

Mongolian Grasslands, Alpine Meadows & Forest Steppe (PA44)

Myanmar Coastal Rainforests & Andaman Sea Islands (IM9)

Nansei Islands Subtropical Evergreen Forests (IM14)

New Guinea & Surrounding Islands (AU13)

New Zealand (AU1)

North Alaskan Tundra (NA3)

North Australian Tropical Savannas (AU8)

North Congolian Lowland Forests (AT15)

North Indian Tropical Forests & Sundarbans (IM6)

North Indomalayan Deserts & Scrub Forest (IM4)

Northeastern American Mixed Forests (NA10)

Northern Amazonian Forests (NT20)

Northern Deccan & Odisha Tropical Forests (IM7)

Northern Great Lakes Forests (NA11)

Northern Prairie & Aspen Forests (NA12)

Northern Sahara Deserts, Savannas & Marshes (PA24)

Northwest Canadian Taiga, Lakes, & Wetlands (NA7)

Northwest Intermountain Conifer Forests (NA14)

Ogasawara Subtropical Islands (OC10)

Ordos Plateau Steppe & Mountain Conifer Forests (PA42)

Ozarks Mixed Forests (NA22)

Pacific Northwest Coastal Forests (NA15)

Palau & Caroline Tropical Islands (OC8)

Pantanal Flooded Grasslands & Dry Forests (NT12)

Patagonia Steppe & Low Mountains (NT2)

Peninsular Malaysian & Sumatran Tropical Rainforests (IM18)

Persian Deserts & Mountain Woodlands (PA29)

Philippines & Sulu Sea Tropical Forests (IM15)

Pontic Steppe Grasslands (PA16)

Queensland Tropical Rainforests & Savannas (AU9)

Red Sea, Arabian Deserts & Salt Marshes (PA26)

Rio de la Plata Grasslands (NT3)

Russian Arctic Desert Islands (PA1)

Sahel Acacia Savannas (AT23)

Salas y Gómez & Easter Islands (OC1)

Samoa & West Polynesian Tropical Islands (OC5)

Sayan Mountain Conifer Forests, Alpine Meadows & Steppe (PA36)

Scandinavian Birch & Coastal Conifer Forests (PA3)

Sea of Okhotsk Coastal Taiga, Meadows & Tundra (PA6)

Seychelles & Comoros Tropical Islands (AT5)

Siberian Boreal Forests & Mountain Tundra (PA7)

Siberian Hemiboreal Forests & Steppe (PA35)

Sichuan Basin & Central Mountain Forests (PA51)

Sierra Madre Forests & Mexican Drylands (NA29)

Solomon Islands (AU12)

South African Cape Shrublands & Mountain Forests (AT2)

South American Coastal Deserts (NT8)

South Australian Mediterranean Forests, Woodlands & Scrub (AU5)

South Caspian Coastal & Mountain Mixed Forests (PA28)

South China Subtropical Evergreen & Monsoon Forests (IM13)

South Congolian Forest-Savannas & Coastal Scarp (AT13)

South Mediterranean Mixed Woodlands & Forests (PA23)

South Red Sea & Gulf of Aden Coastal Drylands (AT22)

Southeast African Subtropical Grasslands (AT8)

Southeast Indonesian Dry Forest Islands (AU15)

Southeast Polynesian Islands (OC3)

Southeast Savannas & Riparian Forests (NA25)

Southern Amazonian Forests (NT17)

Southern Mixed Forests & Blackland Prairies (NA28)

Southern Prairie Mixed Grasslands (NA20)

Southern Sahara Deserts & Mountain Woodlands (PA25)

Southwest African Coastal Drylands (AT10)

St. Helena & Ascension Islands (AT18)

Subantarctic Antipodes Islands (AU16)

Subantarctic Indian Ocean Islands (AN3)

Sulawesi & Maluku Islands (AU14)

Taklimakan Desert & Lowland Deciduous Forests (PA39)

Tian Shan-Pamir Grasslands, Mountain Steppe & Conifer Forests (PA31)

Tibetan-Pamir Alpine Steppes, Shrublands & Mountain Forests (PA41)

Tristan Volcanic Islands (AT1)

Ural Mountains & West Eurasian Taiga Forests (PA8)

Vanuatu Islands (AU11)

Venezuelan Coast (NT23)

Victoria Basin & Albertine Rift Forests (AT12)

West African Coastal Forests & Savanna (AT19)

West Australian Dry Coastal Shrublands (AU6)

West European Coastal Mixed Forests (PA10)

West Sudanian Savanna (AT20)

Western Amazonian Forests & Plains (NT18)

Western Gulf Coastal Grasslands (NA27)

Yucatan & Veracruz Mixed Forests (NT27)

Zagros Mountain Forests & East Anatolian Steppe (PA27)