Where can one find information about the government census?
You can find information about the UK Census on the website of the Office for National Statistics. For the US Census you can find information at the United States Census Bureau website.
The UK government conducts a large number of different censuses: of people, of businesses, and so on. The 10-yearly population census is just one of many but I am assuming that you are referring to it. The Office for National Statistics has published a great deal of detail about the population census and the related link will give you the necessary information and additional links for further information.