Chicago is 67% larger than Las Vegas.
Area: 608 km2 calculated
Chicago is the third most populous city in the United States, after New York City and Los Angeles. With 2.7 million residents, it is the most populous city in both the U.S. state of Illinois and the American Midwest. Wikipedia
Area: 363 km2 calculated
Las Vegas, officially the City of Las Vegas and often known as simply Vegas, is the most populous city in the state of Nevada and the county seat of Clark County. Wikipedia