The Boston Mountains is a Level III ecoregion designated by the Environmental Protection Agency (EPA) in the U.S. states of Arkansas and Oklahoma. Part of the Ozarks, the Boston Mountains are a deeply dissected plateau. The ecoregion is steeper than the adjacent Springfield Plateau to the north, and bordered on the south by the Arkansas Valley. The Oklahoma portion of the range is locally referred to as the Cookson Hills. There are several theories of how the mountains were named, though apparently none are related to the Massachusetts city.
The Ouachita Mountains, simply referred to as the Ouachitas, are a mountain range in western Arkansas and southeastern Oklahoma. They are formed by a thick succession of highly deformed Paleozoic strata constituting the Ouachita Fold and Thrust Belt, one of the important orogenic belts of North America. The Ouachitas continue in the subsurface to the northeast, where they make a poorly understood connection with the Appalachians and to the southwest, where they join with the Marathon uplift area of West Texas. Together with the Ozark Plateaus, the Ouachitas form the U.S. Interior Highlands. The highest natural point is Mount Magazine at 2,753 feet (839 m).
The Himalayan subtropical pine forests are a large subtropical coniferous forest ecoregion covering portions of Bhutan, India, Nepal, and Pakistan.
The Northern Pacific coastal forests are temperate coniferous forest ecoregion of the Pacific coast of North America. It occupies a narrow coastal zone of Alaska, between the Pacific Ocean and the northernmost Pacific Coast Ranges, covering an area of 23,300 square miles, extending from the Alexander Archipelago in southeast Alaska along the Gulf of Alaska to the western Kenai Peninsula and eastern Kodiak Island. The Pacific Coastal Mountain icefields and tundra ecoregion lies inland, at higher elevations in the Coast Mountains. The ecoregion receives high rainfall, which varies considerably based on exposure and elevation. It contains a quarter of the world's remaining temperate rain forest.
The central U.S. hardwood forests comprise a temperate broadleaf and mixed forests ecoregion in the Eastern United States, as defined by the World Wildlife Fund. It has one of the most diverse herbaceous plant floras of ecoregions in North America.
The Petén–Veracruz moist forests is an ecoregion of the tropical and subtropical moist broadleaf forest biome found in Belize, Guatemala, and Mexico.
The geography of Arkansas varies widely. The state is covered by mountains, river valleys, forests, lakes, and bayous in addition to the cities of Arkansas. Hot Springs National Park features bubbling springs of hot water, formerly sought across the country for their healing properties. Crowley's Ridge is a geological anomaly rising above the surrounding lowlands of the Mississippi embayment.
The Willamette Valley ecoregion is a Level III ecoregion designated by the United States Environmental Protection Agency in the U.S. states of Oregon and Washington. Slightly larger than the Willamette Valley for which it is named, the ecoregion contains fluvial terraces and floodplains of the Willamette River system, scattered hills, buttes, and adjacent foothills. It is distinguished from the neighboring Coast Range, Cascades, and Klamath Mountains ecoregions by lower precipitation, lower elevation, less relief, and a different mosaic of vegetation. Mean annual rainfall is 37 to 60 inches, and summers are generally dry. Historically, the region was covered by rolling prairies, oak savanna, coniferous forests, extensive wetlands, and deciduous riparian forests. Today, it contains the bulk of Oregon's population, industry, commerce, and agriculture. Productive soils and a temperate climate make it one of the most important agricultural areas in Oregon.
The Klamath Mountains ecoregion of Oregon and California lies inland and north of the Coast Range ecoregion, extending from the Umpqua River in the north to the Sacramento Valley in the south. It encompasses the highly dissected ridges, foothills, and valleys of the Klamath and Siskiyou Mountains. It corresponds to the Level III ecoregion designated by the Environmental Protection Agency and to the Klamath-Siskiyou forests ecoregion designated by the World Wide Fund for Nature.
The California montane chaparral and woodlands is an ecoregion defined by the World Wildlife Fund, spanning 7,900 square miles (20,000 km2) of mountains in the Transverse Ranges, Peninsular Ranges, and Coast Ranges of southern and central California. The ecoregion is part of the larger California chaparral and woodlands ecoregion, and belongs to the Mediterranean forests, woodlands, and scrub biome.
The Cascade Mountains leeward forests are a temperate coniferous forest ecoregion of North America, as defined by the World Wildlife Fund (WWF) categorization system.
The Eastern Great Lakes lowland forests is a temperate broadleaf and mixed forest ecoregion of North America, as defined by the World Wildlife Fund. It lies mostly in south and eastern Ontario and Quebec in Canada, and Upstate New York and Vermont in the United States.
The Alberta Mountain forests are a temperate coniferous forests ecoregion of Western Canada, as defined by the World Wildlife Fund (WWF) categorization system.
The Alberta–British Columbia foothills forests are a temperate coniferous forests ecoregion of Western Canada, as defined by the World Wildlife Fund (WWF) categorization system. This ecoregion borders Canada's taiga and contains a mix of subarctic forest and temperate forest species as a result. This makes the region an ecotone region, or a region that acts as a buffer between two other biomes.
The Arizona Mountains forests are a temperate coniferous forests ecoregion of the southwest United States with a rich variety of woodland habitats and wildlife.
The Wyoming Basin shrub steppe ecoregion, within the deserts and xeric shrublands biome, is a shrub steppe in the northwestern United States.
The Colorado Rockies forests is a temperate coniferous forest ecoregion of the United States.
The Wasatch and Uinta montane forest is a temperate coniferous forest ecoregion in the Wasatch Range and Uinta Mountains of the western Rocky Mountains system, in the Western United States.
The central forest–grasslands transition is a prairie ecoregion of the central United States, an ecotone between eastern forests and the North American Great Plains. It is a classification defined by the World Wildlife Fund.
The Arkansas Valley is a Level III ecoregion designated by the Environmental Protection Agency (EPA) in the U.S. states of Arkansas and Oklahoma. It parallels the Arkansas River between the flat plains of western Oklahoma and the Arkansas Delta, dividing the Ozarks and the Ouachita Mountains with the broad valleys created by the river's floodplain, occasionally interrupted by low hills, scattered ridges, and mountains. In Arkansas, the region is often known as the Arkansas River Valley, especially when describing the history and culture of the region.
