St. George is a city located in the southwestern part of the U.S. state of Utah on the Utah-Arizona border, and the county seat of Washington County, Utah. It is the principal city of and is included in the St. George Metropolitan Statistical Area. The city is 117 miles (188 km) northeast of Las Vegas, Nevada, and 303 miles (488 km) south-southwest of Salt Lake City on Interstate 15. As of 2012, the US Census Bureau estimated St. George had a population of 75,561. St. George was the second fastest-growing metropolitan area in the United States, only after Greeley, Colorado, in 2005. This trend continued through 2007, when growth slowed substantially. In 2012, the metropolitan area (defined as Washington County) had an estimated 144,809 residents.