Aerial of downtown Chattanooga

Metropolitan Chattanooga grew faster than most of Tennessee last year, according to government population estimates released Thursday.

The U.S. Bureau of the Census estimates the six-county Chattanooga area added 4,150 people during 2011, growing at a pace nearly 50 percent faster than the nation as a whole. Among Tennessee's biggest metro areas, only Nashville grew at a faster pace last year.

But in eight counties surrounding Chattanooga in Southeast Tennessee and Northwest Georgia, the population declined last year, according to the census bureau.

Among Tennessee's 95 counties, government demographers estimate the population declined in 45 counties, mostly in rural areas outside the state's major metro areas.

"Overall, Tennessee grew at just about the same rate as the nationwide average, but two thirds of that growth was in the biggest counties and the fastest growth rates were in suburban counties in metro areas," said Randy Gustafson, director of the Tennessee State Data Center at the University of Tennessee. "People want to live in proximity to their jobs, which are generally in the larger cities. But many would prefer not to live in the larger cities, especially in the South."

Among the 21 counties in the Chattanooga region, the fastest growing was Sequatchie County, which grew by more than 1.5 percent.

"People are finding out about Sequatchie County and with Highway 111 it's very easy to get to our county from Chattanooga," Sequatchie County Executive Claude Lewis said.

"Lewis Mountain on Highway 111 is one of our fastest growing areas and Fredonia Mountain (a retirement community above Dunlap) is drawing many residents to our area," Lewis said.

Sequatchie ranked among the fastest-growing counties in all of Tennessee. The other counties in the Volunteer State with the fastest growth rates were communities in Middle Tennessee -- Wilson, Montgomery and Rutherford counties.

But while urban and suburban counties grew last year, many rural counties just outside of metro areas, the so-called "exurbs," lost population across the country, according to the census bureau estimates.

"The heyday of exurbs may well be behind us," Yale University economist Robert J. Shiller told the Associated Press.

Shiller, co-creator of a Standard & Poor's housing index, identified the risk of a housing bubble before the collapse in 2008. Shiller believes America is now at a turning point, shifting away from faraway suburbs to cities amid higher gasoline prices.

That may be hurting areas like Polk County, Tenn. The biggest percentage drop in population in the Chattanooga area last year was in Polk County, which lost 0.3 percent of its residents.

But Polk County Executive Hoyt Firestone questioned the population estimate.

"We're a small county, but I don't believe we've lost population, " he said. "The census estimates have been wrong in the past, and I think they're probably wrong this time."

The estimates are the first released since the official 2010 Census tallies were issued last year.

The Associated Press contributed to this report. Follow the latest Chattanooga news on Facebook.