Washington County, anchored by St. George, continues to be the nation's fastest growing metro area with a 2006 population of 126,312 and a six-year growth rate of 40 percent, according to a report released today by the U.S. Census Bureau.

St. George Mayor Dan McArthur said in the days before air conditioning became commonplace, the southwestern Utah community "was not desirable."

"Brigham Young had to call people to settle it," he said. "After the first year, of the 309 families, only about half of them were still there."

Now, he said, "it is very desirable," with clean air, a warm climate and relatively low elevation. That's reflected in strong growth since the mid-1990s.

Also showing strong growth was the Provo-Orem metro area, which ranked sixth nationally in growth from April 1, 2000, to July 1, 2006. Provo-Orem, which encompasses Utah and Juab counties, grew by 26 percent, or 97,402 people, to 474,180.

In Utah County, the hot spots are largely new communities in the northwest, such as Eagle Mountain and Saratoga Springs, along with established communities such as Lehi and American Fork. Meanwhile, those seeking to escape the county's urbanization are also starting to move south to Juab County, said Utah County Commissioner Larry Ellertson.

"New areas are developing that a decade ago were just beginning or had not begun," he said. "Now they're cities of 15,000 to 20,000."

The Census Bureau looks at metro areas as distinct from counties. Metropolitan statistical areas have an urban core of at least 50,000 people and adjacent territory that has a high degree of social and economic integration with the core. Micropolitan statistical areas are similar but with urban cores of 10,000 to 50,000.

When compared with other metro areas, such as the Salt Lake or Provo-Orem metro areas, Washington County's growth rate is No. 1 in the nation. But, although Washington County's metro area lies within the county borders, when the county is compared with other counties of more than 10,000 people, it ranked only 19th in growth nationally from 2000 to 2006. And its one-year growth rate was actually surpassed by Wasatch County.

By contrast, when Washington County is compared to other metro areas around the nation, it ranks No. 1 in growth since 2000.

"St. George is consistently one of the fastest growing areas in the nation," said Robert Spendlove, manager of demographic and economic analysis for the Governor's Office of Planning and Budget. "The St. George area has had very strong growth for the entire decade of the 2000s."

The data show that St. George's growth has been largely due to people moving in, said Pam Perlich, senior research economist at the University of Utah. Provo-Orem, in contrast, saw most of its growth through births. So did Salt Lake, where there was a net influx of immigrants but a net domestic outmigration.