Manhattan is the most densely populated borough of New York City, its economic and administrative center, and the city's historical birthplace. The borough is coterminous with New York County, founded on November 1, 1683 as one of the original counties of the U.S. state of New York. The borough consists mostly of Manhattan Island, bounded by the East, Hudson, and Harlem Rivers, and also includes several small adjacent islands and Marble Hill, a small neighborhood on the U.S. mainland.
Manhattan is often described as the cultural and financial capital of the world and hosts the United Nations Headquarters. Anchored by Wall Street in the Financial District of Lower Manhattan, New York City has been called both the most economically powerful city and the leading financial center of the world, and Manhattan is home to the world's two largest stock exchanges by total market capitalization: the New York Stock Exchange and NASDAQ. Many multinational media conglomerates are based in the borough. Historically documented to have been purchased by Dutch colonists from Native Americans in 1626, for 60 guilders or about $24 in 1626 and US$1050 today. Manhattan real estate has since become among the most expensive in the world, with the value of Manhattan Island, including real estate, estimated to exceed US$3 trillion in 2013; residential property sale prices in Manhattan typically exceeded US$1,400 per square foot ($15,000/m2) as of 2016.
Although New York County is the United States' second-smallest county by land area (larger only than Kalawao County, Hawaii), it is also the most densely populated U.S. county. It is also one of the most densely populated areas in the world, with a census-estimated 2015 population of 1,644,518 living in a land area of 22.83 square miles (59.13 km2), or 72,033 residents per square mile (27,812/km2), higher than the density of any individual American city. On business days, the influx of commuters increases that number to over 3.9 million, or more than 170,000 people per square mile (65,600/km2). Manhattan has the third-largest population of New York City's five boroughs, after Brooklyn and Queens, and is the smallest borough in terms of land area.
Many districts and landmarks in Manhattan have become well known, as New York City received a record of nearly 60 million tourists in 2015, and Manhattan hosts three of the world's 10 most-visited tourist attractions in 2013: Times Square, Central Park, and Grand Central Terminal. The borough hosts many world-renowned bridges, such as the Brooklyn Bridge; skyscrapers such as the Empire State Building, one of the tallest skyscrapers in the world; and parks, such as Central Park. There are many historically significant places in Manhattan: Chinatown incorporates the highest concentration of Chinese people in the Western Hemisphere, and the Stonewall Inn in Greenwich Village is considered the birthplace of the modern gay rights movement. The City of New York was founded at the southern tip of Manhattan, and the borough houses New York City Hall, the seat of the City's Government. Numerous colleges and universities are located in Manhattan, including Columbia University, New York University, and Rockefeller University, which have been ranked among the top 35 in the world.
Manhattan's many neighborhoods are not named according to any particular convention. Some are geographical (the Upper East Side), or ethnically descriptive (Little Italy). Others are acronyms, such as TriBeCa (for "TRIangle BElow CAnal Street") or SoHo ("SOuth of HOuston"), or the far more recent vintages NoLIta ("NOrth of Little ITAly") and NoMad ("NOrth of MADison Square Park"). Harlem is a name from the Dutch colonial era after Haarlem, a city in the Netherlands. Alphabet City comprises Avenues A, B, C, and D, to which its name refers. Some have simple folkloric names, such as Hell's Kitchen, alongside their more official but lesser used title (in this case, Clinton).
Some neighborhoods, such as SoHo, are commercial and known for upscale shopping. Others, such as Greenwich Village, the Lower East Side, Alphabet City and the East Village, have long been associated with the Bohemian subculture. Chelsea is a neighborhood with a large gay population, and recently a center of New York's art industry and nightlife. Washington Heights is a vibrant neighborhood of immigrants from the Dominican Republic. Chinatown has a dense population of people of Chinese descent. Koreatown is roughly bounded by 5th and 6th Avenues, between 31st and 36th Streets. Rose Hill features a growing number of Indian restaurants and spice shops along a stretch of Lexington Avenue between 25th and 30th Streets which has become known as Curry Hill.
In Manhattan, uptown means north (more precisely north-northeast, which is the direction the island and its street grid system is oriented) and downtown means south (south-southwest). This usage differs from that of most American cities, where downtown refers to the central business district. Manhattan has two central business districts, the Financial District at the southern tip of the island, and Midtown Manhattan. The term uptown also refers to the northern part of Manhattan above 72nd Street and downtown to the southern portion below 14th Street, with Midtown covering the area in between, though definitions can be rather fluid depending on the situation.
Fifth Avenue roughly bisects Manhattan Island and acts as the demarcation line for east/west designations (e.g., East 27th Street, West 42nd Street); street addresses start at Fifth Avenue and increase heading away from Fifth Avenue, at a rate of 100 per block on most streets. South of Waverly Place, Fifth Avenue terminates and Broadway becomes the east/west demarcation line. Though the grid does start with 1st Street, just north of Houston Street (the southernmost street divided in west and east portions; pronounced HOW-stin), the grid does not fully take hold until north of 14th Street, where nearly all east-west streets are numerically identified, which increase from south to north to 220th Street, the highest numbered street on the island. Streets in Midtown are usually one way with a few exceptions (14th, 23rd, 34th, and 42nd for example). The rule of thumb is that odd-numbered streets run west, while even-numbered streets run east.