The Las Vegas Valley is a major metropolitan area in the southern part of the U.S. state of Nevada, and the second largest in the Southwestern United States. The state's largest urban agglomeration, the Las Vegas Metropolitan Statistical Area is coextensive since 2003 with Clark County, Nevada. The Valley is largely defined by the Las Vegas Valley landfo…The Las Vegas Valley is a major metropolitan area in the southern part of the U.S. state of Nevada, and the second largest in the Southwestern United States. The state's largest urban agglomeration, the Las Vegas Metropolitan Statistical Area is coextensive since 2003 with Clark County, Nevada. The Valley is largely defined by the Las Vegas Valley landform, a 600 sq mi basin area surrounded by mountains to the north, south, east and west of the metropolitan area. The Valley is home to the three largest incorporated cities in Nevada: Las Vegas, Henderson and North Las Vegas. Eleven unincorporated towns governed by the Clark County government are part of the Las Vegas Township and constitute the largest community in the state of Nevada.