Cook County, Illinois is 42 times larger than Manhattan (NYC borough).
Area: 2,468 km2 calculated
Population: 5,231,351 (2012)
Cook County is a county in the United States state of Illinois. As of the 2010 census, the population was 5,194,675. Wikipedia
Area: 59 km2 calculated
Population: 1,619,090 (2012)
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