St. George is a city located in the southwestern part of the U.S. state of Utah, and the county seat of Washington County, Utah. It is the principal city of and is included in the St. George, Utah Metropolitan Statistical Area. The city is 119 miles (192 km) northeast of Las Vegas, Nevada, and 303 miles (488 km) south of Salt Lake City on Interstate 15. According to the U.S. Census Bureau, St. George had a population of 72,718 in 2007, up from 49,728 in 2000. In 2005, St. George surpassed Layton as the eighth-largest city in Utah. From 1990 to 2000, St. George beat Las Vegas by a mere 0.6% as the fastest-growing metropolitan area in the U.S. This trend has continued, with St. George being declared the second fastest-growing metropolitan area in the U.S. in September 2005. In 2007, the metropolitan area had an estimated 140,908 residents. The population of St. George and surrounding cities in 2050 is projected to be at more than 700,000 residents. St. George is the population and commercial center of Utah's Dixie, a nickname given to the area when Mormon pioneers grew cotton in the warm climate. St. George's trademark is its geology — red bluffs make up the northern part of the city with two peaks covered in lava rock in the city's center. The northeastern edges of the Mojave Desert are visible to the south. Zion National Park can be seen to the east, and the Pine Valley Mountains loom over the city to the north and northwest. The climate has more in common with the Desert Southwest than the rest of the state, with scorching hot summers and mild, mostly snowless winters. The city has recently developed into a major retirement destination.