NEW YORK (CNNMoney.com) - Elk Grove, Calif., is the fastest growing city of more than 100,000 in the United States, according to the latest estimates from the Census Bureau released Wednesday.

The young city, a suburb south of Sacramento that incorporated only six years ago, grew by 12 percent to 112,338 in the 12 months ended July 1, 2005.

Three other California cities joined Elk Grove on the top 10 list: Moreno Valley (No. 6), Rancho Cucamonga (No. 7) and Irvine (No. 10).

Florida had three cities on the list led by Port St. Lucie, with a population increase of 11 percent to 131,692.

Other states represented were Arizona with Gilbert (No. 4) and Chandler (No. 9) and Nevada, where North Las Vegas, No. 2, had an 11.4 percent jump.

In terms of sheer numbers, Phoenix added more people than any other city - 44,456 more people, a 3.1 percent rise.

The most populous city in the country, New York, suffered a population loss for the first time since the official Census count in 2000. The Big Apple lost more than 20,000 residents. Its population still totaled 8.1 million, more than twice as many as second place city, Los Angeles, pop. 3.8 million.

Two cities in the list of most populous cities changed positions during the 12-month period. San Antonio nudged past San Diego to go into seventh place with 1.3 million. San Diego actually lost population, falling 8,276 to 1.25 million.

Other big-city losers included Boston, which dropped 1.5 percent, Detroit (minus 1.3 percent) and New Orleans (minus 1.4 percent). These estimates reflect populations before Hurricane Katrina shattered the Crescent City.

Smaller cities with marked declines include Lansing, Mich., and Athens, Ga. (both down 1.2 percent) and Fayetteville, N. C. and Cincinnati (both minus 1.6 percent). St. Louis' population fell a whopping 1.8 percent and Norfolk, Va. did even worse, down 2.3 percent.