The Bronx is the northernmost of the five boroughs of New York City in the United States. It is coextensive with Bronx County, which is one of the 62 counties of New York State. The borough covers a land area of 42 square miles (109 km2) and had a population of 1,472,654 according to the 2020 census.
Geographically, the Bronx is the only borough located primarily on the mainland. It borders Westchester County to the north, the Hudson River and Manhattan to the west, Queens to the south, and Long Island Sound to the east. In terms of size and demographics, it ranks as the fourth largest borough by both area and population, while maintaining the third highest population density among the boroughs.