WASHINGTON » Their lives on hold for years, young adults are now making big moves in the fledgling economic recovery, leaving college towns or parents’ homes and heading out of state at the highest rate since the height of the housing boom.

New census data released today offer a detailed look at U.S. migration as mobility begins to revive after sliding to a record low last year.

The latest numbers show that young adults 25-29 are the primary out-of-state movers; they had the biggest gain in 13 years as they struck out on their own to test the job market in urban, high-tech meccas such as Washington, D.C.; Denver; Portland, Ore.; Seattle; and Austin, Texas.

In contrast, groups that showed some of the most movement in the housing boom of the last decade (2000-2010) — working professionals, families and would-be retirees — are still mostly locked in place, their out-of-state migration levels stuck at near lows due to underwater mortgages and shrunken retirement portfolios.

The demographic shifts, which analysts say could continue for many more years, are once again rejiggering the housing map.

Out are the super-sized McMansions in far-flung suburbs and in the sprawling Southwest, which helped drive rapid metro area growth in the early to middle part of the last decade in places such as Phoenix; Las Vegas; Orlando, Fla.; and Atlanta. In are new, 300 square-foot “micro” apartments under consideration for wider development in dense cities such as New York, San Francisco, Boston and Seattle, which are seeking to attract young single adults who value affordable spaces in prime locations to call their own.

“Footloose young singles are forming the leading edge of the coming migration wave,” said William H. Frey, a Brookings Institution demographer who reviewed the numbers. He attributed the recent jump in mobility to pent-up demand among young adults who now are ready to “move on a dime” to land a job opportunity.

“We will see their migration rates swell even higher if the jobs become more plentiful,” Frey said. “Families, older professionals and retirees will be latecomers; they have more financial baggage and will need to make more careful decisions about when and where to move.”

Richard Florida, an American urban theorist and professor at the University of Toronto’s Rotman School of Management, called the mobility gain an important sign the U.S. economy is getting back on track.

“Young people are moving out of their parents’ basements and sampling places and sampling careers again,” he said. “After living at home for a while, young people have kind of maxed it out. They are heading to bigger, vibrant cities, predominantly, because they’re looking for economic opportunity and building their social networks.”

About 1.7 percent of the U.S. population moved across state lines to a new home in the 12-month period ending March 2012, up slightly from 1.6 percent in the previous year.

The share of young adults ages 25-29 who moved to a new state was higher, about 3.8 percent. That’s up from 3.4 percent in the previous year and the highest level since the height of the housing boom in 2005, when mobility was 5 percent. The 0.4 percentage point increase in 2012 is also the biggest jump for young adults since 1999, when the rapid rise of Internet startups and the need for young workers during the dot-com bubble drove migration.

Moving rates for college graduates of all ages remained mostly flat at 2 percent.

Among Americans 55 and older, out-of-state moves dipped from the previous year to a low of 0.7 percent. At the height of the housing boom, interstate migration for this group reached well over 1 percent, due mostly to baby boomers opting to retire early to residential hot spots in the South and West.

According to the latest data, some of the biggest winners in recent years have been states such as California, Massachusetts and New York. The states were able to reduce much of the annual losses they suffered in domestic migration during the housing boom, when residents left in mass numbers for wider, more affordable spaces in the Sun Belt and Mountain West. The bigger states also continue to gain relatively more people from higher immigration and births.

Broken down by age and metro area, the Washington, D.C., area ranked at the top of destinations for young adults in the 2009-2011 period, rocketing up from 45th in 2006-2008. The area has been boosted by its promise of more plentiful government-related jobs, as well as a continuing influx of students attending area universities and its up-and-coming neighborhoods.

Texas metro areas including Houston, Austin, Dallas and San Antonio, which already were on the rise before the recession hit in late 2007, have remained a strong draw for young adults due to in large part to their thriving energy and high-tech industries. They ranked second, fifth, sixth and ninth, respectively, in terms of youth migration.

Denver and Portland, Ore., rounded out the top five at No. 3 and No. 4.

Separate census data released earlier this year showed that most of America’s largest cities were growing at a faster rate than their surrounding suburbs for the first time in a century, driven mostly by young adults. That also has prompted city planners to devise ways to attract young adults, who generally desire no-strings-attached apartment living and close proximity to potential jobs.

New York Mayor Michael Bloomberg in July invited architects to design an apartment building of “micro-units” no more than 300 square feet. The city envisions a future in which the young and the cash-poor will flock to these dwellings, having grown weary of “doubling up” with friends or family in the economic downturn.

In San Francisco, developers are seeking permission to rent out apartments as small as 220 square feet, a little more than twice the size of some prison cells.

Kenneth Johnson, a senior demographer at the University of New Hampshire, said it’s hard to predict how much migration ultimately will pick up given the uncertainty in the economy. He said the people making the biggest moves in the coming years likely will be those who feel they must: young adults in search of jobs, couples with small children seeking better schools, new retirees desiring high-amenity recreational living.

“I suspect the recession has sobered the American population about migration,” Johnson said.

The census findings are based on the Current Population Survey as of March 2012, as well as comparisons of the 2006-2008 and the 2009-2011 American Community Survey to provide a snapshot of every U.S. community with at least 20,000 residents. Figures from the 2011 American Community Survey also are used to establish broader trends.