Bigger, older cities are losing ground.
The Sacramento suburb grew by 11.6 percent last year, to 112,000 people, typifying America's appetite for open spaces, affordable homes and suburban living. Once a rural farming community, Elk Grove has given way to sprawling development, fueled by a short commute to Sacramento and local employers such as Apple Computer.
"Ten to 15 years ago is when the housing started coming in. That was followed by the businesses," says Janet Toppenberg, president and CEO of the Elk Grove Chamber of Commerce.
Americans have been moving west and south for decades, and last year was no different. All but three of the 50 fastest-growing cities from 2004 to 2005 were in those regions of the country, with many in California and Florida, according to Census Bureau estimates Wednesday. The estimates were for cities with populations of 100,000 or more.
Elk Grove was followed in the top five by North Las Vegas, Nevada; Port St. Lucie, Florida; Gilbert, Arizona, and Cape Coral, Florida.
All five are suburban, and all have fewer than 200,000 residents.
"We have a pattern that is consistent across the country," said Hans Johnson, a research fellow at the Public Policy Institute of California. "Families choose to move to areas where they can buy more housing for less money and often with better schools."
Americans also are moving away from many of the nation's biggest cities, though the reasons vary with the cities.
People are following jobs out of struggling Midwestern cities. Others are leaving expensive Northeastern and Western cities in search of more affordable homes. And people are fleeing big cities everywhere in search of better schools.
New York remained America's largest city, with 8.1 million people. The city has added 135,000 people since 2000, but it lost 21,500 from 2004 to 2005, more than any other city.
Detroit, with its struggling economy, has lost 65,000 people since 2000, the most of any city. Philadelphia, which has lost about 50,000 manufacturing jobs since 2000, has lost 54,000 people during the same period.
San Francisco, with the highest real estate prices in the United States, has lost 37,000 people since 2000, according to the Census Bureau.
The bureau issues annual population estimates based on building permits, housing units and other changes since its 2000 headcount.
States sometimes dispute those estimates based on their own calculations. For example, California officials estimate that San Francisco has grown by 22,000 people since 2000, rather than shrinking. But even if the city did add people, it did so at a much slower rate than cities in the center of the state, said John Malson, a research manager for the state Department of Finance.
"The housing market out here has gone nuts, especially in the coastal areas," Malson said.
"The Central Valley is still more affordable than the coast," he added. "A lot of people are moving out from the (San Francisco) Bay area."
Most of the big cities that gained population were in the South, according to the Census Bureau.
In overall numbers, Phoenix added the most people — 44,400 — from 2004 to 2005, giving it a population of nearly 1.5 million.
New Orleans, an exception in the South, had already lost population before Hurricane Katrina. The city lost about 30,000 people from 2000 to 2005, setting its population at 455,000, the Census Bureau said in an estimate made before the hurricane scattered hundreds of thousands of people.
Local officials estimate that New Orleans has rebounded to about 221,000 people since the storm.