The 3,247 figure is an increase of 240 percent over the number of homeless tallied in the 2007 survey when 1,314 people were determined to be homeless.
The increase is attributed to a different methodology used to count the homeless, although 1.3 percent of the homeless said their home was foreclosed and another 4.5 percent said their landlord stopped renting or re-used the property.
Thirty-four percent said they were homeless because they lost their job and 69 percent said not being able to afford rent was the biggest obstacle to securing permanent housing, according to the report. About 16 percent blamed alcohol or drug use for being homeless.
Forty-seven percent said they had been homeless a year or more and 53 percent said this was their first episode of homelessness.
Thirty percent were considered chronically homeless - individuals with a disabling condition who have been homeless a year or longer or who have experienced four or more episodes of homelessness within the past three years.
The report was presented Tuesday morning to the Sonoma County Board of Supervisors.
Jenny Helbraun Abramson of the Sonoma County Continuum of Care planning group, said 20 percent of the county's homeless are in the west county where there is no homeless shelter. Nearly 47 percent are in Santa Rosa and nearby unincorporated areas.
The report also stated 14 percent of the homeless are under age 18 and 67 percent of the homeless are male.
Fourteen percent of the homeless were working full or part-time and 53 percent said they were not receiving money from government sources, according to the report.
The census used state of the art methods in the U.S. Department of Housing and Urban Development's 2006 Guide to Counting the Unsheltered Homeless People and the homeless count was taken in all 86 of the county's census tracts, Abramson said.
The methodology does not include homeless people sleeping on a couch in a friend's or relative's home, and people in hospitals, jails or rehabilitation centers.
"This is a very literal definition of homeless," said Peter Connery, project director of Applied Survey Research of Watsonville and San Jose which complied the data in the report.