Growth rate since April 2000: 89.7%
Pinal County got swept up in the Phoenix housing bubble, one of the nation's most frantic during the boom. Prices in the metro area rose 127% from January 2000 through June 2006, the peak of the market.
The county's economy, once driven by ranching and cotton growing, is now dominated by service industries. Many residents commute to Phoenix for work.
Arizona is one of the states hardest hit by the housing bust. The resulting lower home prices in Phoenix have caused migration out to Pinal to ease. Population growth slowed to 3.6% in the 12 months ended July 1, 2009, after averaging well over 7% for most of the decade.
According to one real estate agent, some residents have pulled up stakes and moved back to the Valley of the Sun (Phoenix) as housing prices there plunged.
The housing market in Pinal has been battered by foreclosures with one out of every 106 households hit by some kind of delinquency filing in May, the highest rate for any Arizona county. There were 582 households in the county lost to bank repossessions during that month.NEXT: Rockwall County, Texas