The census figures also show that Ascension and Livingston parishes experienced the highest percentage population growth among the state’s 64 parishes over the past decade. Each grew by just under 40 percent while the state’s population increased by 1.4 percent to 4.53 million.

The census figures reflect a marked shift in Louisiana’s population from the New Orleans metro area to Louisiana’s capital region since Hurricane Katrina in 2005.

Adam Knapp, president and chief executive officer of the Baton Rouge Area Chamber, said the 2010 census figures show the nine-parish capital region has grown at an even-faster pace than researchers were projecting.

The capital region now has a population of just more than 800,000, Knapp said, which is an important threshold for economic development purposes and attracting new businesses.

"We’re considered a major market now,” Knapp said. "If you think of it as a boxing metaphor, we're in a different weight class.”

He said the capital region’s population was 705,973 in 2000 and it wasn’t expected to surpass 800,000 until some time in 2013.

"It’s fantastic news,” Knapp said.

Ascension and Livingston parishes were the fastest-growing parishes in the state in terms of their percentage growth rates of just under 40 percent, the census report shows.

Ascension’s population grew by 30,588 over the past decade to 107,215; Livingston’s grew by 36,212 to 128,026.

East Baton Rouge Parish’s population grew at a slower pace, 6.6 percent, rising 27,319 to 440,171 over the decade.

Lafayette Parish also showed robust population growth of 16.31 percent — 31,075 people over the decade, from a population of 190,503 to 221,578.

St. Tammany Parish added the largest number of people over the decade, 42,472 — from 191,268 to 233,740.

But a post-Katrina exodus resulted in dramatic population losses for most of the New Orleans metro area.

Orleans Parish saw its population drop by 29 percent, from 484,674 to 343,829. The population of Jefferson Parish fell from 455,466 to 432,552, a 5 percent decline.

Hard-hit St. Bernard Parish lost nearly half its population, falling from 67,229 in 2000 to 35,897 in the 2010 census.

East Baton Rouge Parish Mayor-President Kip Holden did not respond to telephone and e-mail messages left with his staff on Thursday seeking comment on the latest census figures.

Mayor Pro Tem Mike Walker, who chairs the Metro Council, said the population growth is a good thing but poses challenges

"We’re continuing to gain population in tough times, so that’s encouraging,” Walker said.

But, he said, keeping up with infrastructure improvements needed to support a growing population is a continuing challenge.

Walker said he’s hopeful the latest census figures will qualify the parish for more federal dollars to pay for road work and other public improvements.

"We can’t slow down,” Walker said. "We have to keep up with the growth.”

Ascension Parish President Tommy Martinez said he thought population growth for Ascension might be even higher than was reflected in the latest census data.

"As you drive around Ascension Parish, you can see the growth, and it’s continuing,” Martinez said.

He said balancing growth can be tough when it comes at such a rapid pace.

"Right now we have to build a school a year,” Martinez said. "We’re behind the eight ball on infrastructure, and we know that.”

He said the parish is handling the pressures that come with the population growth by working together.

"We’ve got a great sheriff’s office and school system, and everybody works together here,” Martinez said.

Livingston Parish President Mike Grimmer said the latest numbers are no surprise and reflect what he sees in growing school populations and more traffic on the streets.

"It’s good growth for us because we’re starting to get more retail businesses and more jobs,” Grimmer said. "That’s something the parish has been light on in the past.”

He said it also means more tax revenue.

Troy C. Blanchard, an LSU demographer, said Livingston and Ascension parishes have been "listed among the top 100 fastest-growing counties in the United States in the past couple of years.”

Blanchard said one big unanswered question from the latest census figures is what the future holds for the New Orleans metro area.

He said there was an assumption that people who moved after Katrina would come back, but the population has yet to rebound.

The New Orleans metro area has a lot of infrastructure and potential for growth, Blanchard said, and it will be interesting to see what happens over the next decade.

The Baton Rouge metro area has a different challenge as it grows into a big city, Blanchard said.

"It’s a very exciting time for south Louisiana, for our area, at least,” he said.

He said one issue confronting Baton Rouge is a "hollowing out” of the urban core as people move to suburban communities like Central and Zachary or to Livingston and Ascension parishes.

Knapp noted that the capital region’s population grew by almost 14 percent over the past decade, from 705,973 to 802,484. By comparison the state’s total population grew by 1.4 percent, from 4,468,976 to 4,533,372.