The country's fifth largest city is in the desert, according to the latest Census Bureau estimates. And though it is only half the size of the next largest city, the nation's No. 1 city in terms of population has more than twice as many people as its closet rival.

Yup, New York reigns supreme as the largest city in the United States, with a population of 8.2 million. The next largest city is Los Angeles, which has just 3.8 million residents. Chicago is third with 2.8 million inhabitants and Houston is fourth with 2.1 million. Phoenix, the aforementioned desert city, moved into fifth place, according to the latest count, moving ahead of Philadelphia. The head count in Phoenix in 2006 was 1.5 million. In Philadelphia, it was 1.45 million. The switch is further evidence of a shift in the U.S. population that began decades ago.

In 1910 -- nearly a century ago -- all of the ten most populous cities were within approximately 500 miles of the Canadian border. Now, seven of the top ten and three of the top five are in states that border Mexico.

In another big change, only three of the largest cities in 1910 -- New York, Chicago and Philadelphia -- remain on the current list. At the same time, three of the current top ten -- Phoenix, San Jose and San Diego -- were not even among the top 100 largest cities 97 years ago, while three others -- Dallas, Houston and San Antonio -- had populations of less than 100,000.

Three of the 10 fastest-growing cities are in the Dallas metro area: McKinney (second), Grand Prairie (sixth) and Denton (ninth). In the same general vicinity, Ft. Worth just missed the list, ranking 11th.

Phoenix had the largest population increase of any city between 2005 and 2006, adding more than 43,000 residents. But Texas dominated the list of the 10 highest numerical gainers, with San Antonio, Ft. Worth, Houston, Austin and Dallas each making the top 10. Three other Texas cities made the list of 25 biggest numerical gainers.

New York -- 8,214,426
Los Angeles -- 3,849,378
Chicago -- 2,833,321
Houston -- 2,144,491
Phoenix -- 1,512,986
Philadelphia -- 1,448,394
San Antonio -- 1,296,682
San Diego -- 1,256,951
Dallas -- 1,232,940
San Jose -- 929,936