The westernmost end of Long Island contains the New York City boroughs of Brooklyn (Kings County) and Queens (Queens County). The central and eastern portions contain the suburban Nassau and Suffolk Counties. However, colloquial usage of the term “Long Island” usually refers only to Nassau and Suffolk Counties. For example, the Federal Reserve Bank of New York has a district named “Long Island (Nassau-Suffolk Metro Division).” At least as late as 1911, locations in Queens were still commonly referred to as being on Long Island. Some institutions in the New York City section of the island use the island’s names, like Long Island University and Long Island Jewish Medical Center.
In 1985, the United States Supreme Court ruled in United States v. Maine that Long Island is legally not an island, because New York State’s boundaries contained its offshore soil and seabeds. Despite the legal decision the United States Board on Geographic Names still considers Long Island an island, because it is surrounded by water.
Nassau County is more densely developed than Suffolk County. While affluent overall, Nassau County has pockets of more pronounced wealth with estates covering greater acreage within the Gold Coast of the North Shore and the Five Towns area on the South Shore. South Shore communities are built along protected wetlands of the island and contain white sandy beaches of Outer Barrier Islands fronting on the Atlantic Ocean. Dutch and English settlers from the time before the American Revolutionary War, as well as communities of Native Americans, populated the island. The 19th century saw the infusion of the wealthiest Americans in the so-called Gold Coast of the North Shore, where wealthy Americans and Europeans in the Gilded Age built lavish country homes.
In its easternmost sections, Suffolk County remains semi-rural, as in Greenport on the North Fork and some of the periphery of the area prominently known as The Hamptons, although summer tourism swells the population in those areas. The North Fork peninsula of Suffolk County’s East End has developed a burgeoning Wine Country region. In addition, the South Fork peninsula is known for beach communities, including the Hamptons, and for the Montauk Point Lighthouse at the eastern tip of the island. The Pine Barrens is a preserved pine forest encompassing much of eastern Suffolk County.
Long Island is one of the most densely populated regions in the United States. As of the United States 2010 Census, the total population of all four counties of Long Island was 7,568,304, which was 39% of the population of the State of New York. As of 2017, the proportion of New York City residents living on Long Island had risen to 58%, given the 5,007,353 residents living in Brooklyn or Queens. Furthermore, the proportion of New York State’s population residing on Long Island has also been increasing, with Long Island’s Census-estimated population increasing 4.0% since 2010, to 7,869,820 in 2017, representing 39.6% of New York State’s Census-estimated 2017 population of 19,849,399 and with a population density of 5,617.3 inhabitants per square mile (2,168.9/km) on Long Island. Long Island’s population is greater than 37 of the 50 U.S. states.
As of the 2010 census, the combined population of Nassau and Suffolk Counties was 2,832,882 people; Suffolk County’s share being 1,493,350 and Nassau County’s 1,339,532. Nassau County had a larger population for decades, but Suffolk County surpassed it in the 1990 census as growth and development continued to spread eastward. As Suffolk County has more than three times the land area of Nassau County, the latter still has a much higher population density and is growing faster in the 21st century, given its proximity to New York City. According to the U.S. Census Bureau’s 2008 American Community Survey, Nassau and Suffolk Counties had the 10th and 26th highest median household incomes in the nation, respectively.
Population figures from the U.S. Census Bureau Census 2010
show that whites are the largest racial group in all four counties, and are in the majority in Nassau and Suffolk Counties. In 2002, The New York Times cited a study by the non-profit group ERASE Racism, which determined that Nassau and Suffolk Counties constitute the most racially segregated suburbs in the United States.
In contrast, Queens is the most ethnically diverse county in the United States and the most diverse urban area in the world.
According to a 2000 report on religion, which asked congregations to respond, Catholics are the largest religious group on Long Island, with non-affiliated in second place. Catholics make up 52% of the population of Nassau and Suffolk, versus 22% for the country as a whole, with Jews at 16% and 7%, respectively, versus 1.7% nationwide. Only a small percentage of Protestants responded, 7% and 8% respectively, for Nassau and Suffolk Counties. This is in contrast with 23% for the entire country on the same survey, and 50% on self-identification surveys.
A growing population of nearly half a million Chinese Americans now live on Long Island. Rapidly expanding Chinatowns have developed in Brooklyn (布魯克林) and Queens (皇后), with Chinese immigrants also moving into Nassau County, as did earlier European immigrants, such as the Irish and Italians. The busy intersection of Main Street, Kissena Boulevard, and 41st Avenue defines the center of Downtown Flushing and the Flushing Chinatown (法拉盛華埠), known as the “Chinese Times Square” or the “Chinese Manhattan”. The segment of Main Street between Kissena Boulevard and Roosevelt Avenue, punctuated by the Long Island Rail Road trestle overpass, represents the cultural heart of the Flushing Chinatown. Housing over 30,000 individuals born in China alone, the largest by this metric outside Asia, Flushing has become home to the largest and one of the fastest-growing Chinatowns in the world as the heart of over 250,000 ethnic Chinese in Queens, representing the largest Chinese population of any U.S. municipality other than New York City in total. Conversely, the Flushing Chinatown has also become the epicenter of organized prostitution in the United States, importing women from China, Korea, Thailand, and Eastern Europe to sustain the underground North American sex trade.
More recently, a Little India (लघु भारत) community has emerged in Hicksville, Nassau County, spreading eastward from the more established Little India enclaves in Queens. Likewise, the Long Island Koreatown (롱 아일랜드 코리아타운) originated in Flushing, Queens, and is expanding eastward along Northern Boulevard and into Nassau County.
Long Island is home to two Native American reservations, Poospatuck Reservation, and Shinnecock Reservation, both in Suffolk County. Numerous island place names are Native American in origin.
A 2010 article in The New York Times stated that the expansion of the immigrant workforce on Long Island has not displaced any jobs from other Long Island residents. Half of the immigrants on Long Island hold white-collar positions.
The Counties of Nassau and Suffolk have been long renowned for their affluence. Long Island is home to some of the wealthiest communities in the United States, including The Hamptons, on the East End of the South Shore of Suffolk County; the Gold Coast, in the vicinity of the island’s North Shore, along Long Island Sound; and increasingly, the western shoreline of Brooklyn, facing Manhattan. In 2016, according to Business Insider, the 11962 zip code encompassing Sagaponack, within Southampton, was listed as the most expensive in the U.S., with a median home sale price of $8.5 million.