The Bronx (/brɒŋks/) is a borough of New York City, coextensive with Bronx County, in the U.S. state of New York, the third-most-densely populated county in the United States. It is south of Westchester County; northeast and east of Manhattan, across the Harlem River; and north of Queens, across the East River. The Bronx has a land area of 42 square miles (109 km2) and a population of 1,418,207 in 2019. Of the five boroughs, it has the fourth-largest area, fourth-highest population, and third-highest population density. It is the only borough predominantly on the U.S. mainland. If each borough were its own city, the Bronx would rank as the eighth-most-populous in the United States.