Allegheny Plateau in the context of "Tygart Valley River"

New York, also called New York State, is a state in the northeastern United States. Bordered by the New England states to the east, Canada to the north, and Pennsylvania and New Jersey to the south, its territory extends into both the Atlantic Ocean and the Great Lakes. New York is the fourth-most populous state in the United States, with nearly 20 million residents, and the 27th-largest state by area, with a total area of 54,556 square miles (141,300 km).

New York has a varied geography. The southeastern part of the state, known as Downstate, encompasses New York City, the most populous city in the United States; Long Island, with approximately 40% of the state's population, the nation's most populous island; and the cities, suburbs, and wealthy enclaves of the lower Hudson Valley. These areas are the center of the expansive New York metropolitan area and account for approximately two-thirds of the state's population. The larger Upstate area spreads from the Great Lakes to Lake Champlain and includes the Adirondack Mountains and the Catskill Mountains (part of the wider Appalachian Mountains). The east–west Mohawk River Valley bisects the more mountainous regions of Upstate and flows into the north–south Hudson River valley near the state capital of Albany. Western New York, home to the cities of Buffalo and Rochester, is part of the Great Lakes region and borders Lake Ontario and Lake Erie. Central New York is anchored by the city of Syracuse; between the central and western parts of the state, New York is prominently featured by the Finger Lakes, a popular tourist destination. To the south, along the state border with Pennsylvania, the Southern Tier sits atop the Allegheny Plateau, representing some of the northernmost reaches of Appalachia.

The Finger Lakes are a group of eleven long, narrow, roughly north–south lakes located in an area called the Finger Lakes region in New York, in the United States. This region straddles the northern and transitional edge of the Northern Allegheny Plateau, known as the Finger Lakes Uplands and Gorges ecoregion, and the Ontario Lowlands ecoregion of the Great Lakes Lowlands.

The geological term finger lake refers to a long, narrow lake in an overdeepened glacial valley, while the proper name Finger Lakes goes back to the late 19th century. Cayuga and Seneca Lakes are among the deepest in the United States, measuring 435 and 618 feet (133 and 188 m), respectively, with bottoms well below sea level. Though none of the lakes' widths exceed 3.5 miles (5.6 km), Seneca Lake is 38.1 miles (61.3 km) long, and at 66.9 square miles (173 km) is the largest in total area.

The Catskill Mountains, also known as the Catskills, are a physiographic province and subrange of the larger Appalachian Mountains, located in southeastern New York. As a cultural and geographic region, the Catskills are generally defined as those areas close to or within the borders of the Catskill Park, a 700,000-acre (2,800 km) forest preserve protected from many forms of development under New York state law.

Geologically, the Catskills are a mature dissected plateau, a flat region subsequently uplifted and eroded into sharp relief by watercourses. The Catskills form the northeastern end of the Allegheny Plateau (also known as the Appalachian Plateau).

The Southern Tier is a geographic subregion of the broader upstate region of New York State, geographically situated along or very near the state border with Pennsylvania. Definitions of the region vary widely, but generally encompass counties surrounding the Binghamton, Elmira-Corning, and Jamestown metropolitan areas, along with the land of the Seneca Nation. This region is adjacent to the Northern Tier of Pennsylvania, and both these regions together are known as the Twin Tiers.

Geographically, most of the Southern Tier resides in the Allegheny Plateau of the Appalachian Mountains, with the eastern areas of the region nestled in the western portion of the Catskill Mountains. A longtime home of the Iroquois Confederacy, European settlers moved to the region after the American Revolutionary War. The fertile yet hilly land, combined with sweeping river valleys, led the region to support a combination of manufacturing industries (including large companies such as IBM and Corning Inc.) and farming, but with less development compared to neighboring subregions of upstate. Since the 1950s, the area is often considered to be a part of the Rust Belt, as manufacturing jobs have left the region.

The West Branch Susquehanna River is one of the two principal branches, along with the North Branch, of the Susquehanna River in the Northeastern United States. The North Branch, which rises in upstate New York, is generally regarded as the extension of the main branch, with the shorter West Branch being its principal tributary.

The West Branch, which is 243 miles (391 km) long, is entirely within the state of Pennsylvania, draining a large mountainous area within the Allegheny Plateau in the western part of the state. Along most of its course it meanders past mountain ridges and through water gaps, forming a large zigzag arc through central Pennsylvania around the north end of the Allegheny Mountains. In colonial times, the river valley provided an important route to the Ohio River valley. In the 19th century, its lower valley became a significant industrial heartland of Pennsylvania. In the 20th century, the upper reaches of the West Branch turned a yellow/orange color due to sulfurous drainage from nearby and abandoned deep bituminous coal mines.

The Monongahela River (/məˌnɒŋɡəˈhiːlə/ mə-NONG-gə-HEE-lə, /-ˈheɪ-/ -⁠HAY-), sometimes referred to locally as the Mon (/mɒn/), is a 130-mile-long (210 km) river on the Allegheny Plateau in north-central West Virginia and Southwestern Pennsylvania. The river flows from the confluence of its west and east forks in north-central West Virginia northeasterly into southwestern Pennsylvania, then northerly to Pittsburgh and its confluence with the Allegheny River to form the Ohio River. The river includes a series of locks and dams that makes it navigable.

New York, also called New York state, is a state in the northeastern United States. Bordered by the New England states to the east, Canada to the north, and Pennsylvania and New Jersey to the south, its territory extends into both the Atlantic Ocean and the Great Lakes. New York is the fourth-most populous state in the United States, with nearly 20 million residents, and the 27th-largest state by area, with a total area of 54,556 square miles (141,300 km).

New York has a varied geography. The southeastern part of the state, known as Downstate, encompasses New York City, the most populous city in the United States; Long Island, with approximately 40% of the state's population, the nation's most populous island; and the cities, suburbs, and wealthy enclaves of the lower Hudson Valley. These areas are the center of the expansive New York metropolitan area and account for approximately two-thirds of the state's population. The larger Upstate area spreads from the Great Lakes to Lake Champlain and includes the Adirondack Mountains and the Catskill Mountains (part of the wider Appalachian Mountains). The east–west Mohawk River Valley bisects the more mountainous regions of Upstate and flows into the north–south Hudson River valley near the state capital of Albany. Western New York, home to the cities of Buffalo and Rochester, is part of the Great Lakes region and borders Lake Ontario and Lake Erie. Central New York is anchored by the city of Syracuse; between the central and western parts of the state, New York is prominently featured by the Finger Lakes, a popular tourist destination. To the south, along the state border with Pennsylvania, the Southern Tier sits atop the Allegheny Plateau, representing some of the northernmost reaches of Appalachia.

The Erie people were an Indigenous people of the Northeastern Woodlands historically living on the south shore of Lake Erie. An Iroquoian-speaking tribe, they lived in what is now western New York, northwestern Pennsylvania, and northern Ohio before 1658. Their nation was almost exterminated in the mid-17th century by five years of prolonged warfare with the powerful neighboring Iroquois for helping the Huron in the Beaver Wars for control of the fur trade. Captured survivors were adopted or enslaved by the Iroquois.

Their villages were burned by Haudenosaunee warriors. This destroyed their stored maize and other foods, added to their loss of life, and threatened their future, as they had no way to survive the winter. The attacks likely forced their emigration. The Haudenosaunee Confederacy was known for adopting captives and refugees into their tribes. The surviving Erie are believed to have been largely absorbed by other Iroquoian tribes, particularly families of the Seneca, the westernmost of the Five Nations. Susquehannock families may also have adopted some Erie, as the tribes had shared the hunting grounds of the Allegheny Plateau and Kittanning Path that passed through the gaps of the Allegheny. The members of remnant tribes living among the Iroquois gradually assimilated to the majority cultures, losing their independent tribal identities.