The fastest growing U.S. cities

NEW YORK (CNNMoney.com) -- What's the fastest-growing American city with more than half a million people?

If you guessed Ft. Worth, you are correct. Dallas' next-door neighbor added more than 20 percent to its population from July 2000 through July 2006, according to the latest estimates from the U.S. Census Bureau.

But if you answered New York, you were also correct. With 205,750 new citizens, Gotham added more residents than any city in the United States since 2000. That's enough new New Yorkers to fill a city the size of Boise, Idaho, bringing its total number to 8,214,826 - an all-time high.

New York is one of the few major old industrial towns that have not experienced a substantial shrinking in the number of its core residents. The top 10 cities of a hundred years ago would have included places like Baltimore (now at 631,366, the 19th largest), Boston ( 590,763, 22nd), Cleveland (444,313, 40th) and St Louis (347,181, 52nd).

Many of the older cities are only losing population from their core areas while the suburbs around them are still growing. But even taking into account total metro-area growth, the newer sunbelt cities are growing at a faster rate than older, industrial towns.

Each of the 10 biggest cities once lay within 500 miles of the Canadian border. Now, seven of the top 10 are sun-belt cities, closer to Chihuahua than Toronto.

Some of the nation's biggest cities today were mere blips on the radar at the turn of 20th-century America. Los Angeles, the nation's second largest city with 3,849,378 people, had a population of just over 100,000 in 1900.

Dallas, Houston, San Antonio, San Diego and San Jose, Calif. all had fewer than 100,000.

Phoenix, which 100 years ago was not even among the 100 most populous cities, grew by more than 40,000 residents during the 12 months ended July 1, 2006. Phoenix passed Philadelphia, which has lost about 70,000 residents during the 2000s, to become the fifth biggest American city.

The biggest loser of the 2000s, outside of New Orleans, where hurricane-related losses drove more than half the city's residents away, has been Detroit. Motown endured a net loss of 80,000 people during the 2000s, leaving the population at less than half of its 1950s heyday.

Cleveland (- 6.9 percent), Pittsburgh (-6.5 percent) and Buffalo (-5.7 percent) also continued to show big losses since 2000.

The fastest growing of any of the cities of more than 50,000 population was McKinney, Texas, which lies in the path of the outward expansion of Dallas. It has nearly doubled in size since 2000 to 107,530.

Other growth spurts occurred in Gilbert, Arizona (73.9 percent to 191,517), North Las Vegas (71.1 percent to 197,567) and Port St Lucie, Florida (61.9 percent to 143,868).

North Las Vegas led the nation in growth rate for the 12 months ended July 1, 2006. Its population increased 11.9 percent. Second was McKinney at 11.1 percent and Port St. Lucie was third at 9.9 percent.

Twelve-month numerical leaders included Phoenix (43,192), San Antonio (33,084) and Ft. Worth (30,202).