U.S. growth continues to shift south, west

WASHINGTON — Phoenix has overtaken Philadelphia as the nation's fifth-largest city, underscoring decades of population losses in the United States' industrial centers.

The nation's population has nearly doubled since 1950, adding about 150 million people. But of the 20 largest cities at the middle of the last century, all but four — including Seattle — have shrunk, some by a lot.

Detroit, Cleveland, Pittsburgh, St. Louis and Buffalo, N.Y., lost more than half their population in the past half-century or so.

Seattle bucked the trend, with its population up by 25 percent since 1950, from 467,591 to 582,454 in 2006, according to Census Bureau figures. It is now the 23rd-largest city in the country.

Philadelphia, meanwhile, lost nearly one-third of its residents, slipping to about 1.4 million people in 2006, according to estimates being released today by the Census Bureau.

"It's hard to think of the cradle of liberty being overtaken by a rough-and-tumble, independent Western town, but that tells you something about the nature of our country," says William Frey, a demographer for the University of Michigan and the Brookings Institution. "We're a country that's always seeking new horizons."

Like many big cities in the Northeast and Midwest, Philadelphia has suffered through a decline in the nation's manufacturing economy.

City officials have vowed to rebound.

"Philadelphia is not going to disappear," said Gary Jastrzab, deputy executive director of the city planning commission.

The Census Bureau is releasing 2006 population estimates for U.S. cities today. The Associated Press compared those estimates with population totals from the 1950 census.

Phoenix was barely in the top 100 cities in 1950; it ranked 99th, with about 107,000 people. Last year, it had 1.5 million.

Phoenix added 43,000 people from 2005-06, more than any other city, according to Census Bureau estimates. It was followed by San Antonio; Fort Worth, Texas; Houston; and North Las Vegas, Nev.

New Orleans, still struggling to rebuild after Hurricane Katrina, lost the most people, about 228,000. The Census Bureau estimated the city's population at 223,400 in 2006, a little less than half its size before the storm.

Americans have been migrating south and west for decades in search of better job opportunities and warmer climates. They also have been moving to the suburbs and beyond, in search of bigger yards and houses, lower crime rates and better schools.

The Census Bureau numbers also show that seven of the 10 most populous U.S. cities are within about 500 miles of the Mexican border. In 1910, all 10 of the biggest cities were within 500 miles of the Canadian border.

Many older cities are trying to reinvent themselves, relying on the universities, health centers and cultural attractions that have long been desirable, said William Frey, a demographer at the Brookings Institution, a Washington think tank.

"It used to be that the city was the whole regional economy. Now, it is just the center," Frey said.

Material from USA Today is included in this report.