One of the five boroughs of New York City. Also the only one on the mainland of North America, separated from Manhattan by the Harlem River. The current population is around 1,300,000, making it the fourth most populous borough. The South Bronx, the part of the borough that dominates the popular imagination, is one of the quintessentially ghetto places in America.

The area was originally owned by the Bronks family, as far back as Dutch times, and came to be known as ‘The Bronks,’ and later “The Bronx.” It was incorporated as Bronx county. The name is officially “Bronx,” but it is usually called “The Bronx.” The Bronx is extremely hilly, and is crossed by a series of steep north-south running ridges, which fade into northern Manhattan. In the farthest west portion of the borough, these ridges are steep and sometimes shear cliffs, which separate and isolate unique neighborhoods such as University Heights and Riverdale.

In the late 19th century, New York City, at that time only the island of Manhattan, annexed southern portions of what is now the Bronx. There was some housing development, but not much. Upon the consolidation of New York City as we know it in 1898, the Bronx became one of the five boroughs of the city. At this point, like Queens and Staten Island, it was mostly farm land and forest.

The arrival of elevated commuter railroads from Manhattan spurred residential development in the southern part of the borough and extended along the elevated lines and boulevards such as the Grand Concourse. These elevateds included the Dyre Avenue Elevated, the Jerome Avenue elevated, the Third Avenue Elevated, and the New York, Westchester, and Boston railway. The first three were tied into the Interboro Rapid Transit company's new Manhattan subway lines, while the later was added to the subway in the 50’s. There was also industrial and warehouse development in the south and east, notably in the Hunt’s Point area, home of the America's largest fish market. The construction of Yankee Stadium, the Bronx zoo, Fordham University, and The Heights campus of NYU were milestones of this era. The Independent Subway arrived in the early 30’s with the Concourse Line.

The population of this era was working and middle class Jews, Italians, and Irish, usually moving up from crowded tenement areas of Manhattan. Still today, the Bronx has its own Little Italy, along Arthur avenue. Unique to the Bronx among the boroughs, development in this era was almost exclusively large apartment buildings, as opposed to a mix of apartments, brownstones, and detached homes. Today architects identify a characteristic ‘Bronx style’ of apartment building.

This borough of apartment buildings was only a generation old when it fell victim to the urban schemes of Robert Moses. Huge swaths of it were demolished by freeways and parkways, and replaced with large monolithic housing projects on large grass lots, ushering in the urban decay that would characterize the borough. Suburbanization after the war dramatically altered the demographics, and the Bronx, especially the South Bronx, became almost entirely Black and Puerto Rican. The housing projects and remaining crumbling apartment buildings became synonymous with ‘Urban Decay.’ There was also in this period some working- and middle class housing development in the eastern and northern Bronx, which was home to the Italian community portrayed in Summer of Sam.

Many aspects of the hip-hop subculture originated in the Bronx. Kool Herc, who invented the idea of DJing break beats in 1971 did so in the Bronx.

The Riverdale neighborhood, isolated from the rest of the borough by steep cliffs, developed uniquely. Inaccessible by subways, it features large country houses on narrow lanes meandering through the hilly woods. It resembles Vermont more than New York City. Another isolated community is City Island, which resembles a mid-Atlantic fishing village.

In recent years urban decay has stabilized and the Bronx has received new immigration. Dominicans, Mexicans, and Albanians now have significant communities. Still, it has not followed Brooklyn and Queens in becoming a microcosm of the world.