The Northeastern Highlands Ecoregion is a Level III ecoregion designated by the United States Environmental Protection Agency (EPA) in the U.S. states of Vermont, New Hampshire, Massachusetts, Maine, Connecticut, New York, New Jersey, and Pennsylvania. The ecoregion extends from the northern tip of Maine and runs south along the Appalachian Mountain Range into eastern Pennsylvania. Discontiguous sections are located among New York's Adirondack Mountains, Catskill Range, and Tug Hill. The largest portion of the Northeastern Highlands ecoregion includes several sub mountain ranges, including the Berkshires, Green Mountains, Taconic, and White Mountains.
The Northeastern Highlands region is underlain by metamorphic rock and glacial till. The ecoregion is flanked by several others including the Acadian Plains and Hills, Eastern Great Lakes Lowlands, Northeastern Coastal Zone, Northern Allegheny Plateau, Ridge and Valley, and Northern Piedmont ecoregions. The elevation generally ranges from to at the top of Mount Washington, the region's highest and most prominent point.
The region is characterized by heat during the summer, the chilling winters, and the nutrient-poor podzols and other cryic (perennially frozen) soil types of the region which support boreal (north) and broadleaf (south) forests that cover the majority of the region. Ecotourism, forestry, and agriculture are the predominant land uses of the sparsely populated region.Griffith, G.E., Omernik, J.M., Bryce, S.A., Royte, J., Hoar, W.D., Homer, J.W., Keirstead, D., Metzler, K.J., and Hellyer, G., 2009, Ecoregions of New England (color poster with map, descriptive text, summary tables, and photographs): Reston, Virginia, U.S. Geological Survey (map scale 1:1,325,000). Though much of the region was once cleared to make farmland, much of it has reverted into natural forested areas. To a lesser extent, dairy and crops are still grown in lowland valleys and beef cattle on upland pastures. The ecoregion has been subdivided into thirty-three Level IV ecoregions.
Native fauna
Mammals
Ursus americanus (American black bear) Odocoileus virginianus (white-tailed deer) Alces alces (moose) Lynx rufus (bobcat) Canis latrans (coyote) Mephitis mephitis (skunk) Procyon lotor (raccoon) Tamias striatus (chipmunk) Scurinae spp. (squirrel) Didelphis virginiana (opossum) Erethizon dorsatum (porcupine) Pekania pennanti (fisher)
The Northeastern Highlands ecoregion was within the range of other large mammals at the onset of European settlement, including boreal woodland caribou — which inhabited northern Vermont, New Hampshire, and Maine — as well as American bison, which estimates have placed in western portions of the Catskills and Adirondacks. Puma and Cervus canadensis canadensis (eastern elk) also once inhabited a majority of the region.
Birds
Meleagris gallopavo (eastern turkey) Colinus virginianus (northern bobwhite) Ardea herodias (great blue heron) Anatidae spp. (ducks) Gavia immer (common loon) A host of other bird, reptile, amphibian, and fish species.
First Nations peoples Before European settlement, the region was inhabited by two principal indigenous groups, the Algonquian and Iroquoian peoples. The Algonquian community represents one of the largest and most geographically dispersed Native American language groups. They held prominence along the Atlantic Coast and within the inland areas adjacent to the St. Lawrence River and the vicinity of the Great Lakes. The Iroquoian peoples form an ethnolinguistic collective originating from the eastern expanse of North America. Their traditional territories, often denoted as Iroquoia, extend from the northern mouth of the St. Lawrence River to present-day North Carolina in the southern reaches.
Level IV ecoregions
58a. Taconic Mountains The Taconic Mountains ecoregion runs north-south for along New York's eastern border, spanning eastern New York, southwestern Vermont, far western Massachusetts, and the northwest corner of Connecticut. The range appears rugged despite lower elevations compared to the nearby Catskills and Adirondacks, with elevations of and local relief of . Predominantly metamorphic bedrock gives rise to a varied landscape of steep and gentle slopes, narrow valleys, springs, and caves due to soluble limestone. The humid continental climate, frost-free growing season of 90-135 days, and slightly elevated precipitation characterize the region. The northern-southern expanse leads to discernible forest type shifts.
Northern hardwood forests thrive on cooler mid-to-high elevation sites, housing Acer saccharum (sugar maple), Fagus grandifolia (American beech), Tilia americana (American basswood), and Betula alleghaniensis (yellow birch), with Picea and Abies species (spruce-fir) at the highest elevations. Oak-hickory forests with species like Quercus rubra (northern red oak) and Carya ovata (shagbark hickory) dominate lower, drier slopes. Pinus rigida (pitch pine) and Quercus ilicifolia (bear oak) cover the highest elevations in the south. Isolated old-growth forests remain in Mount Washington State Forest and Mount Everett State Reservation.
The area is sparsely populated with minimal agricultural use; forests encompass most of the region. It borders the Taconic Foothills to the west, the Rensselaer Plateau to the center, and the Western New England Marble Valleys to the east, with a small border with the Champlain Lowlands to the north.
Taconic Ridge State Park and Taconic Trail State Park are components of the Taconic Mountains region, providing protected spaces for both conservation and recreation. Taconic Ridge State Park spans areas of New York and Massachusetts including portions of the Taconic Crest Trail. Taconic Trail State Park, located in Massachusetts, encompasses several woodlands and offers a network of trails, including sections of the Appalachian Trail.
The highest peak in the Taconic Mountains is Mount Equinox in Vermont at . Despite being mostly private property, it contains sizable state forests, parks, and protected preserves. Conservation efforts involve organizations like the Berkshire Natural Resources Council and The Nature Conservancy, with designated areas under the Forest Legacy Program.
58aa. Acid Sensitive Adirondacks
The Acid Sensitive Adirondacks derive their name from the underlying bedrock which has a low acid-neutralizing capacity and is one of the regions of the Northeastern Highlands that has been most affected by acid rain. The Acid Sensitive Adirondacks constitute the largest level IV region of the Adirondack Mountains. Acid rain has acidified the region's lakes to the point where they are uninhabitable for fish; terrestrial effects of acid rain have resulted in leaching of calcium and release of aluminum, which has resulted in tree mortality. Tree cover in the region is dominated by conifers including red, white, and black spruce, as well as balsam fir, red maple, yellow birch, and black cherry.
The Acid Sensitive Adirondacks are in the southwestern portion of the Adirondack Park and are composed of the Independence River Wild Forest, the Black River Wild Forest, and the Moose River Plains. The western gateway community of Old Forge is central to the eco-region.
58ab. Northern and Western Adirondack Foothills The Northern and Western Adirondack Foothills encompass a curved expanse in upstate New York, encircling the higher elevations of the Adirondacks to the north, west, and southwest. This area serves as a transitional zone between the mountainous terrain and the adjacent lowlands. The landscape gradually ascends from around in elevation across a span of . The area is blanketed by thick glacial deposits, which hinder stream drainage in multiple sections. Despite its steep incline, the region generally features a high water table and abundant wetlands, an unusual characteristic. The narrowest and most abrupt elevation shifts occur in the southwest and western sectors. Conversely, the northern part of the region widens slightly, showcasing a more gentle gradient and smoother slopes.
Originally, spruce trees dominated the forests here. However, extensive logging activities led to their depletion, with only a few specific soil types supporting their resurgence. Presently, the area is dominated by second-growth northern hardwood forests, including tree species like sugar maple, American beech, black cherry, and yellow birch. The western foothills and northern outwash areas host substantial populations of eastern white pine, while aspen and birch prevail more in the north. Areas with shallow or water-saturated soils foster coniferous forests composed of red spruce, white spruce, black spruce, and balsam fir. Notably, bogs are home to dominant black spruce and tamarack trees, accompanied by understory vegetation such as sheep laurel and labrador tea. Agricultural activities are limited in this vicinity, primarily focused on cultivating forage crops. Logging stands as a more active land use, with significant public lands preserved for wildlife habitats and recreational and tourism pursuits. Surrounding the Acid-Sensitive Adirondacks, except for the northeast where it borders the Central Adirondacks in a single location, this region holds a unique position. Towards the northeastern extremity, where the foothills envelop the Adirondacks, the Eastern Adirondack Foothills border it. This adjoining region, distinguished ecologically, is treated as a distinct entity. Lowering in elevation, the Northern and Western Adirondack Foothills neighbor the Upper St. Lawrence Valley to the north and west, along with the Mohawk Valley to the south and southwest.
58ac. Eastern Adirondack Foothills The Eastern Adirondack Foothills serve as a pivotal intermediary zone nestled between the western Adirondacks and the lowlands situated to the east. This geographical domain envelops the eastern and southeastern peripheries of the Adirondack Mountains, manifesting climatic and geological distinctions that set it apart from the foothills encompassing the mountains' northern, western, and southwestern sectors.
In the northern expanse of this locale, the predominant bedrock substratum primarily comprises limestone and anorthosite formations. Meanwhile, the southern reaches of this area showcase a blend of these foundational rock types in conjunction with others.
The climatic conditions prevailing within this region exhibit characteristics of a humid continental climate. Particularly pronounced in the northern domain, the rain shadow effect induces lower precipitation levels than those typically encountered in the broader surroundings. However, the moisture content remains sufficiently elevated to sustain luxuriant forests. The topographical configuration is accentuated by the presence of expansive valleys incised by the Saranac and Ausable rivers in the northeast. These valleys facilitate the penetration of milder climatic influences from lower-lying areas into the foothills. In the southern sector, the landscape becomes more rugged following a relatively abrupt transition. This results in climatic consistency throughout this extensive north-south stretch, thereby mitigating the impact of colder winters as one proceeds northward. The average frost-free interval spans between 90 and 145 days.
Historically, the primeval forest cover encompassing this realm was characterized by northern hardwood forests, interspersed with select species from the Appalachian oak forest biome at the lower gradients that abut the Hudson Valley and Champlain Lowlands.
Despite its modest population density, the Eastern Adirondack Foothills are more settled than their higher-altitude counterparts within the Adirondacks. The majority of development is concentrated along major thoroughfares traversing the territory, converging within a handful of petite municipalities situated along these arterial routes.