The Bronx (NYC borough) is 375 times larger than Mobile, Alabama.
Area: 0 km2 calculated
Mobile is the county seat of Mobile County, Alabama. The population within the city limits was 195,111 as of the 2010 United States Census, making it the third most populous city in the U.S. 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