Source:  Matt O'Brien, THE CONTRA COSTA TIMES, 7/20/11
 

An estimated half-million illegal immigrants live in the Bay Area, according to a study that is one of the first to try to measure the number of local residents living in the U.S. illegally.

The report by the Public Policy Institute of California used tax returns, previous national estimates and mathematical models to determine that 563,000 illegal immigrants live in the Bay Area, about 8 percent of the region's total population.

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