All six counties showed moderate population growth from 2008 to 2009, with all but San Diego County growing at a stronger rate than the year before.
It's the latest sign that the region is recovering from the declines in population seen in the middle of the decade, some experts said.
"Things aren't wonderful in Southern California, but you are seeing some industries that are growing or in the process of rebounding," said Jack Kyser, senior vice president and chief economist for the Los Angeles County Economic Development Corp. He and others believe the population numbers are one indicator of the slow rebound after a severe recession that resulted in population decreases in some parts of the region.
Southern California's population grew at a higher rate than the state's population as a whole, according to the data. The gains in 2009 were small but significant. The population of Los Angeles County as of July 1, 2009, the latest date available, was 9,848,011, according to the census estimates. That number was up 68,757 from the year before.
Between 2006 and 2007, L.A. actually lost 25,897 people -- a trend seen in other Southern California counties as the economy soured.
The census data don't fully explain where the population increases were coming from. But Dowell Myers, a professor of urban planning and demography at USC, said some of the newcomers to Southern California are probably younger people from other parts of the country deciding to give the region a try. A portion of the increase is births.
For years, Southern California was a magnet for new residents, who came for both the balmy climate and strong economy. But steep housing prices, the exodus of major corporations and jobs, and the high cost of living tarnished that allure.
The new numbers, said Kyser, offer hope that some of the worst economic times for the region could be over. "What you are seeing is that people are not going to the traditional hot spots like Las Vegas, like Phoenix, even like Florida, because of the housing problems and also the economic problems in those areas," he said.
Kyser predicted that Southern California will continue to see a steady increase in population -- as long as the economy slowly improves. "As the economy recovers over the course of this year, people are going to be looking around and saying, 'Where do we go? If we go to Las Vegas, that's a one-trick pony, and the casino business is struggling.' In Los Angeles, there's more opportunity."
The population estimates released this week are based on census data from 2000 and represent the last population estimates before the decennial count, which is now being conducted and the results of which will be released in December.
In Orange County, the population was at 3,026,786, up 1.26%. Ventura County grew at about the same rate as the state, climbing just 1% to 802,983.
Riverside County, population 2,125,440 in 2009, had the region's highest growth rate at 1.8%. Growth in San Bernardino County mirrored Los Angeles' at 0.64%. The county's population reached 2,017,673.
More information on their demographics will be available later in the year, when the Census Bureau releases its annual American Community Survey, which provides information about the race, ethnicity and socio-economics of the region's residents.
Myers cautioned that the census numbers released this week can be misleading because they are not derived from what he called "perfect data."
But he said that the population uptick is a clear indication that many of the people who put their lives on hold when the economy crashed have begun to make plans again.
"You can't hold your breath forever," Myers said. "You had a big downturn, and now you have a little bounce-back."
