Driven by a boom in immigration, the Boston area grew by about 55,000 residents in a recent two-year period, according to new county population estimates by the US Census Bureau.
The population growth in Cambridge’s Middlesex County and Boston’s Suffolk County together accounted for about half the state’s overall growth of about 100,000 new residents between April 2010 and July 2012, the census figures show.
The increase brought the state’s total population to 6,646,144.
Massachusetts’ 1.5 percent growth during the period was less than the nation’s 1.7 rate, but the state is doing well compared with the rest of the region.
“It’s the fastest growing state in the Northeast,” said Susan Strate, population estimates program manager at the UMass Donahue Institute, of the nine-state region, which includes New England, New York, New Jersey, and Pennsylvania.
A large part of the Bay State’s growth was made up of immigrants, said officials who monitor the region’s demographics.
“The big story in Massachusetts in the last 10 years is the increase in the foreign-born population,” said Len Albright, an assistant professor of sociology and public policy at Northeastern University. Without immigrants, the state’s population would have fallen over the past decade, he said.
Boston’s population in 1990 was about 20 percent foreign born; now it is 27 percent, according to the census numbers.
Most of Massachusetts’ recent immigrants came from Latin America and Asia, with Brazil, China, and the Dominican Republic topping the list, according to a report released last month by the Immigrant Learning Center, a nonprofit that runs classes for immigrants and does research.
The kinds of jobs the immigrants took varied widely, as did their incomes, said the report’s authors, Professor Alan Clayton-Mathews of Northeastern University and Professor Paul Watanabe, director of the Institute of Asian American Studies at UMass Boston.
Many became cleaners and maintenance workers, but others found employment in the life sciences, computers, and math, according to the report, citing the US Census 2009 American Community Survey.
More than half the state’s medical scientists are foreign born, said Marcia Hohn , at the center. Average income for immigrants is about $40,851, compared with $46,277 for native born, the report said.
“If you are in science and technology, Boston is the place to be,” said Hohn. “There is a lot of energy and knowledge and interacting between the people in the science and technology worlds.”
“This is not your grandfather’s Greater Boston anymore,” said Marc Draisen, executive director of the Metropolitan Area Planning Council, a regional planning agency, referring to the vast number of languages spoken across the region.
More immigrants means a more vibrant economy, said Strate. “Our growth is looking strong,” she said. The state attracts many immigrants because of its reputation for higher education and well-paying jobs in growing fields like biotechnology, said Strate and Hohn.
Metro areas such as Boston have gained population because they are vibrant, exciting places to live and work, said Barry Bluestone, director of the Dukakis Center for Urban and Regional Policy at Northeastern. It’s a trend seen in other thriving urban centers such as New York and San Francisco, said Draisen.
People are attracted to the Boston region because jobs are there, transportation is good, and there are plenty of cultural attractions and good restaurants, said people who follow the data.
Younger people “are more likely to move to Waltham and Somerville and not Lexington and Concord,” said Bluestone. “The younger generation has less interest in a suburban home and definitely less interest in driving an hour to work. They are more interested in living near work.”
Mark Melnik, deputy director of research for the Boston Redevelopment Authority, said Boston is growing younger — more than one-third of residents are between ages 20 and 34. That’s tops among major US cities, he said, and the percent has grown steadily since 1990.
A major factor benefiting the region is the vast number of institutions of higher education, which have helped it constantly reinvent itself, said Ryan D. Enos, an assistant professor of government at Harvard University. When companies built around manufacturing and computer hardware died off through the decades, health care and other industries have sprung up to replace them.
The census numbers showed that Middlesex easily retained its title as the state’s most populous county, with an estimated population of 1,537,215. Suffolk, the fourth largest county behind Worcester and Essex, grew to 744,426.
Middlesex County also benefits from the growth of Boston, said Albright, as people move there who either cannot afford the city or who work nearby but don’t want to live in the city.
On a percentage basis, Suffolk grew the most, 3.1 percent, tied with tiny Dukes County, made up of Martha’s Vineyard and the Elizabeth Islands, which added about 500 residents, bringing its population up to 17,041.
Only two counties lost population: Barnstable and Berkshire, which shed about 465 and 1,200 people, respectively.
One thing is not a big draw to Massachusetts: “The weather,” said Hohn. “I’ve never heard any immigrant say, I came here for the weather.”
Matt Carroll can be reached at email@example.com. Follow him on Twitter @globemattc.