The Bronx is New York City 's northernmost borough, and it is the only one of the city's five boroughs situated primarily on the United States mainland rather than on an island. If all five boroughs were independent cities, the Bronx would rank as the ninth most populous city in the United States . Author Edgar Allan Poe spent the last years of his life in the Bronx and Hip hop first emerged in the South Bronx in the early 1970s. The Kingpin started out as a common thug in the Bronx and Mary Jane Watson and The Prowler were born there.