The Bronx (NYC borough) is 91% larger than Manhattan (NYC borough).
Area: 59 km2 calculated
Manhattan is the most densely populated of the five boroughs of New York City. The borough is coterminous with New York County, an original county of the U.S. state of New York. Wikipedia
Area: 112 km2 calculated
The Bronx is the northernmost of the five boroughs of New York City, in the U.S. state of New York. Coextensive with Bronx County, it was the last of the 62 counties of New York State to be incorporated. Wikipedia