The lower Hudson Valley cuts through the Appalachian zones of the eastern USA - USGS
The Hudson River valley runs more or less north to south down the eastern edge of New York State, cutting through a series of rock types including Triassic sandstones and redbeds in the south and much more ancient Precambriangneiss in the north (and east). In the Hudson Highlands, the river enters a fjord cut during previous ice ages. To the west lie the extensive Appalachian highlands. In the Tappan Zee region, the west side of the river has high cliffs produced by an erosion-resistant diabase; these cliffs range from 400–800 feet in height.
During the last ice age, the valley was filled by a large glacier that pushed down as far as Long Island. Near the end of the last ice age, the Great Lakes drained south down the Hudson River, from a large glacial lake called Lake Iroquois.Lake Ontario is the remnant of that Lake. Large sand deposits remain from where Lake Iroquois drained into the Hudson; these are now part of the Rome Sand Plains.
The first Dutch settlement was in the 1610s with the establishment of Fort Nassau, a trading post (factorij) south of modern-day Albany, with the purpose of exchanging European goods for beaver pelts. Fort Nassau was later replaced by Fort Orange. During the rest of the 17th century, the Hudson Valley formed the heart of the New Netherland colony operations, with the New Amsterdam settlement on Manhattan serving as a post for supplies and defense of the upriver operations.
The valley became one of the major regions of conflict during the American Revolution. Part of the early strategy of the British was to sever the colonies in two by maintaining control of the river.
Following the building of the Erie Canal, the area became an important industrial center. The canal opened the Hudson Valley and New York City to commerce with the Midwest and Great Lakes regions. However, in the mid 20th century, many of the industrial towns went into decline.
In the early 19th century, popularized by the stories of Washington Irving, the Hudson Valley gained a reputation as a somewhat gothic region inhabited by the remnants of the early days of the Dutch colonization of New York (see, e.g., The Legend of Sleepy Hollow). The area is associated with the Hudson River School, a group of American Romantic painters who worked from about 1830 to 1870.
Morning, Looking East over the Hudson Valley from Catskill Mountains by Frederic Edwin Church (1848), of the Hudson River School
Tourism became a major industry as early as 1810, as elite visitors frequented the mineral water at Ballston Spa and Saratoga Springs for their health. With convenient steamboat connections in New York City, and numerous attractive hotels in romantic settings, tourism became an important industry. Early guidebooks providing suggestions on their itinerary. Middle class women People who read James Fenimore Cooper's novels, or saw the paintings of the Hudson River School, where especially attracted.
The most discussed pollution of the Hudson River is General Electric's contamination of the river with Polychlorinated biphenyls (PCBs) between 1947-77. This pollution caused a range of harmful effects to wildlife and people who eat fish from the river or drink the water. In response to this contamination, activists protested in various ways. Musician Pete Seeger founded the Hudson River Sloop Clearwater and the Clearwater Festival to draw attention to the problem. The activism led to the site being designated as one of the superfund sites. Other kinds of pollution, including mercury contamination and sewage dumping, have caused problems also.
Various responses to pollution are proposed and debated.
The Hudson Valley is divided into three regions: Lower, Middle, and Upper. The following is a list of the counties within the Hudson Valley sorted by region. The Lower Hudson Valley is typically considered part of the Downstate New York region due to its geographical and cultural proximity to New York City
^Levinton, J.S.; Ochron, S.T.P. (2008). "Temporal and geographic trends in mercury concentrations in muscle tissue in five species of hudson river, USA, fish". Environmental Toxicology and Chemistry27 (8): 1691–1697. doi:10.1897/07-438.1. PMID18266478.