Maricopa County, AZ, gained 696,000 residents during the six-year period between 2000 and 2006, the largest numerical increase of the nation's 3,141 counties, according to estimates released last week by the Census Bureau.

The huge jump is greater than the population of all but 15 U.S. cities. Indeed, Maricopa County, which includes Phoenix, has 3.8 million residents, making it the country's fourth largest county.

"The dramatic increase in Maricopa County's population is the main reason Arizona became the nation's fastest-growing state between 2005 and 2006," Census Bureau Director Louis Kincannon said. Population estimates released in December projected that the county added nearly three million residents since the 1970 census, a number Kincannon called "remarkable."

According to the nation's bean counter, Harris County, Texas, had the second largest numeric increase between 2000 and 2006, gaining 486,000 people and bringing the total population to 3.9 million. Riverside, CA (481,000), Los Angeles (429,000), and Clark, NV (402,000), rounded out the top five county gainers.

Of the ten counties that added the largest number of residents during the six-year period, three were in Texas (Harris, Tarrant and Collin), three in California (Riverside, Los Angeles and San Bernardino), and one each were in Georgia (Gwinnett) and Illinois (Will). Of the 20 counties with the largest numerical gains, 19 were located in the South or West.

Los Angeles continues to be the most populous county in the nation, with 9.9 million residents as of July 1, 2006. Cook, IL, is the next largest with 5.3 million inhabitants, followed by Harris, TX, and Maricopa, AZ.

Of those counties or county equivalents that experienced declining populations, Orleans Parish in Louisiana, which was hard hit by Hurricane Katrina, had the largest population loss during the six-year period. Orleans lost 261,000 residents, dropping its population to 223,000.

In contrast, the second biggest "loser" was Wayne County, MI, which lost 89,000 residents. Cook County, IL, the second largest in the country, saw its population decline by 88,000. The populations in Wayne and Cook declined to 2 million and 5.3 million, respectively.

Also noteworthy is that of the ten counties that lost at least 10 percent of their population between 2000 and 2006, half were in Louisiana. St. Bernard Parish saw its population drop by an amazing 76.9 percent, while Orleans Parish lost 53.9 percent of its people.

Florida's Flagler County, which is located along the Atlantic Coast between Daytona Beach and Jacksonville, has been the nation's fastest-growing county since the Census 2000. It's population has grown 66.7 percent during the six year period to 83,000.

Kendall, IL (61.7 percent), and Rockwall, TX (60.5 percent), were the second and third fastest-growing counties.

Interestingly, three of the ten fastest-growing counties between 2000 and 2006 were all in the Atlanta-Sandy Springs-Marietta, GA, metropolitan area: Forsyth, ranking fifth with 53.4 percent growth; Henry, ranking eighth at 49.2 percent; and Paulding, ninth at 48.9 percent.

Among the 20 fastest-growing counties with more than 10,000 people, 13 were in the South, four in the West and three in the Midwest.

Here are some other highlights from the most recent Census Bureau estimates:

• Between 2005 and 2006, half the top ten numeric gainers between 2005 were in Texas -- Harris, Tarrant, Bexar, Collin and Dallas. Maricopa ranked first, though, adding 130,000 residents.

  Also on the top ten list making the list were the counties of Riverside, CA; Clark, NV; Wake, NC, and San Bernardino, CA.

• Chattahoochee County, GA, the home of Fort Benning, grew by 13.2 percent over the period, making it the nation's fastest growing county on a percentage basis. Percentage wise, the other biggest gainers were Pinal, AZ.; Kendall, IL; Rockwall, TX; Flagler, FL; Pearl River, MS; Lyon, NV; Paulding, GA; Ascension Parish, LA, and Sumter, FL.

• Georgia had a nation-leading 14 counties among the 100 fastest-growing counties. Texas followed with 13. Florida had 12.

Published: March 28, 2007

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When Lew Sichelman first started writing about housing in 1969, he was the youngest real estate writer in the country. Now, 37 years later, he's one of the oldest -- and most decorated. He has been rated the top housing columnist in the country by the National Association of Realtors as well as by his peers in the National Association of Real Estate Editors. Indeed, NAREE has recognized his work on numerous occasions. One year - due to his advancing age, he can't recall which one - he earned top honors in the annual NAREE Journalism Contest in three out of the four major writing categories. It was the first time one writer has won so many NAREE awards in a single year. Known for his ability to make even the most difficult topics understandable, Sichelman also has been honored by the National Association of Home Builders and the Mortgage Bankers Association. He began providing in-depth coverage of and consumer-oriented information about housing and housing finance at the Washington Daily News, where he was real estate editor. He held that same position for nine more years at the Washington Star, which purchased the News in 1972. The Star, a so-called "writer's newspaper" which also had the misfortune of being an evening paper, was put out of its misery in 1981, and Sichelman, who had begun self-syndicating his column in 1978, decided to become a full-time columnist. Today, his column, "The Housing Scene," is distributed by United Media to newspapers throughout the country. He also is on the staff of National Mortgage News, an independent newspaper which is considered the bible of the mortgage business. And he writes for numerous other publications, including MarketWatch.com, where he answers readers questions once a week, Sports Illustrated (don't ask), RealtyTimes.com, BigBuilder and others. Sichelman is married, the father of five and grandfather of eleven.