Aurora, Colorado is 2.1 times larger than Manhattan (NYC borough).
Area: 125 km2 calculated
The City of Aurora is a Home Rule Municipality in the State of Colorado, spanning Arapahoe and Adams counties, with the extreme southeastern portion of the city extending into Douglas County. Aurora is one of the principal cities of the Denver-Aurora-Broomfield, CO Metropolitan Statistical Area. Wikipedia
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