Washington is among eight big-city metropolitan regions in which minorities became a majority in the past decade, according to a new analysis of census data showing white population declines in many of the largest metro areas.

Along with Washington, the regions surrounding New York, San Diego, Las Vegas and Memphis have become majority-minority since 2000. Non-Hispanic whites are a minority in 22 of the country’s 100-biggest urban areas.

The white population shrank in raw numbers in 42 of those big-city regions. But every large metro area showed a decline in the percentage of whites.

The shifts reflect the aging of the white population as more people get beyond their childbearing years and the relative youth of the Hispanic and Asian populations fueling most of the growth.

“What’s happened is pivotal,” said William Frey, a demographer with the Brookings Institution who conducted the analysis. “Large metropolitan areas will be the laboratories for change. The measures they take to help minorities assimilate and become part of the labor force will be studied by other parts of the country that are whiter and have­n’t been touched as much by the change.”

Racial and ethnic minorities make up slightly more than half of the residents of the Washington region, according to 2010 Census figures. The region was 55 percent white in 2000 and 64 percent white in 1990.

Not every part of the region has been affected equally.

Whites are minorities in the District and in Maryland’s Montgomery, Prince George’s and Charles counties. In Virginia, Prince William County is majority-minority.

With 55 percent of its residents white, Fairfax County could become majority-minority by the next census. So could Loudoun County, which is 62 percent white. Arlington County is one of the few places in the region where the percentage of whites is on the rise.

In most places, the demographic shift has been so rapid that even the officials tracking it have been stunned.

A report this spring by the Northern Virginia Regional Commission noted that the number of students enrolled in the area’s eight school districts grew by almost 119,000 from 1995 to 2010. The number of white students rose by barely 1,000. The rest were minorities.

“What has happened in the past 15 years in the public schools of Northern Virginia is literally mind-boggling,” the report says. “Even for a region accustomed to constant and accelerated change, the spectacularly swift transformation of the racial and ethnic profile of Northern Virginia’s school-aged population is without precedent.”

When the Metropolitan Washington Council of Governments wanted to offer tips to homeowners and renters facing foreclosure, it printed brochures not only in English and Spanish but in Mandarin Chinese, Vietnamese and Amharic, a language spoken in Ethi­o­pia.

Rep. Gerald E. Connolly (D-Va.) said the growth in racial and ethnic minorities has helped transform places such as Fairfax from reliably moderate Republican domains to ones where Democrats control the Board of Supervisors and that are represented in Congress and the General Assembly by Democrats.

“You’re going to start seeing that demographic impact politically in the outer suburbs” more and more, he predicted.

The census figures offer a glimpse of the future workforce for high-paying, high-skilled jobs and for lower-paying service jobs, said Stephen Fuller, director of the Center for Regional Analysis at George Mason University.

“If we fast-forward to 2020, when we’re out of the doldrums the economy is in today, we’re going to need more workers than we have residents,” he said. “I look at this flow of nonnatives, whether they’re moving here from California or right off the boat from whatever country, as an important source of workers that will enable the economy to grow. “

Fuller said that as more people approach retirement, about 60 percent of the job vacancies created will be filled people who do not live here today. Almost half the jobs will require college educations, but the rest will not. Landscapers, home health aides, waitresses, cashiers and other low-skill positions are often filled by immigrants.

“There are an enormous lot of jobs that aren’t great jobs,” he said. “I don’t know who’s going to do the jobs that have to be done unless people have to because they’re newcomers.”

Frey said the changes over the past decade have altered Washington and the way it is perceived.

“It’s not a traditional immigrant magnet,” he said. “Ten years ago, when you thought of immigrants, you’d think of L.A., New York or San Francisco. You wouldn’t think of Washington. Now it’s moved up on the pecking order.

“It’s a precursor of what’s coming in other places.”