The first census took place in 1790 to determine the number of seats each state would get in the House of Representatives. The once-a-decade count has continued since.
The census 2010 questionnaire is among the shortest in history, with 10 questions about the home and the names, genders, ages and races of people living there.
Questionnaires will be delivered to more than 130 million addresses throughout the nation March 15-17. Each residence will be sent a questionnaire, cover letter and postage-paid return envelope.
Census day is April 1. Questionnaires should be mailed back by then.
Anyone who doesn't receive a questionnaire can pick one up at dozens of Stanislaus County locations, which will have forms in English, Spanish, Chinese, Korean, Vietnamese and Russian.
Participating in the census is mandatory. Those who refuse can be fined up to $5,000.
Those who fill out and mail back their questionnaire on time will not be visited by census takers, but government employees will go to homes over and over until the questionnaires are completed.
The Census Bureau is legally forbidden to share an individual's responses with anyone. Anyone caught revealing information faces up to five years in prison and a $250,000 fine.
All census data will be made public in 72 years, when individual census records will be sent to the National Archives and made available for genealogical research. The 1930 census and all earlier census data is public now and available to look at on numerous Web sites.
Census 2010 population totals for the nation and states will be announced by Dec. 31, along with the apportioned number of seats each state will get in the House of Representatives.
The federal government allocates more than $400 billion annually to states and communities based, in part, on census data.
Census counts led to government distribution of $1,674.22 per person in California in 2008, according to the Brookings Institution, a Washington, D.C., think tank. So for every 1,000 people census 2010 misses, Stanislaus County could lose nearly $1.7 million per year in state and federal funds.
Besides congressional districts, census data helps determine boundaries for state Senate, state Assembly, county supervisor and assorted other college and special district governing board districts.
Cumulative population data gathered by census 2010 eventually will be posted online for free public access. That data will show the number, ages and racial breakdown of residents by neighborhood, city, county, school district, congressional district, state and the nation. The data will not include personal information.