7. Las Vegas is the largest city in the U.S. state of Nevada, and a major city in the United States. As of 2008, the city has a population of 603,093 and the metropolitan area has a population of approximately 1.9 million . The robust economy of Las Vegas has its source in the over 30 million visitors a year Visitor Spending in 2008 : $ 42,800,000,000 etimated.