Before the American Revolutionary War, Upstate was populated by Native Americans, and was home to the Six Nations of the Iroquois Confederacy. The region saw many battles between the Continental Army and the Iroquois, and several treaties drawn up after the war ceded much of the land to settlers of European descent. The development of Upstate New York was spurred by the opening of the Erie Canal in 1825, which greatly eased the transport of goods between the port of New York City and inland cities along the Great Lakes. As a result, Upstate became a hotbed for manufacturing, giving birth to such firms as General Electric, IBM, Kodak, and Xerox, and it welcomed a large influx of immigrants. Since the mid 20th century, American de-industrialization has contributed to economic and population decline. Upstate, and the region is largely considered part of the Rust Belt.
Unlike the New York metropolitan area, Upstate New York contains vast areas of rural land. As a result, Upstate also supports a strong agriculture industry, and is notable for its milk and dairy products, its fruit production (especially apples), and winemaking. New York City is dependent on the natural resources of Upstate for a variety of services, including the city's water supply and electricity. The region is home to several popular tourist and recreational destinations, including Niagara Falls, the Adirondack and Catskill Mountains, and the Finger Lakes.
There is no clear official boundary between Upstate New York and Downstate New York. The broadest usage of the term Upstate New York excludes only New York City and Long Island, which are always considered to be part of Downstate New York; this usage is common among New York City residents. Another usage locates the Upstate/Downstate boundary further north, at the point where New York City's suburbs segue into its exurbs, as the exurbs do not fall within the US Census' urban area. This boundary places most, but not all, of Westchester and Rockland Counties in Downstate, while putting the northwestern edge of Rockland County as well as the northernmost quarter of Westchester County (including Peekskill) in Upstate; area residents often use Interstate 84 to delineate the boundary between upstate and downstate New York.
Yet another definition uses the prior Census definition of the New York metropolitan area, which until 2010 included Westchester, Rockland, and Putnam Counties. This was the definition used by the plaintiffs in the federal redistricting case of Rodriguez v. Pataki. In state law, the definition of the upstate boundary also varies: one definition includes Westchester, Rockland and Putnam in the downstate region; others include Orange and Dutchess Counties, which are both served by Metro-North Railroad lines. Ulster County, and, in the largest state-defined extent of downstate, Columbia County are also sometimes included. The division line between the United States District Court for the Southern District of New York and the United States District Court for the Northern District of New York places Sullivan County and Dutchess County in the Southern District and Ulster and Columbia Counties in the Northern District.
Within New York, surveys have had difficulty determining a consensus. In a 2016 poll of New York voters in which respondents were given four definitions of where Upstate begins to choose from, three were about equally common, selected by between 25% and 30% of respondents each: north of New York City, north of Westchester County, and north of Poughkeepsie in Dutchess County. (The fourth, which also stated north of Poughkeepsie but arbitrarily excluded Buffalo as a unique region neither upstate nor downstate, drew only 7%.) An informal 2018 poll found the Hudson Valley region being the most heavily disputed area in regard to whether it is upstate or downstate.