The first six censuses list only the names of the heads of household. There are no women's names in those first six censuses. The 1850 census was the first to list the entire household by name. It is vital to know how state and county boundaries changed over the years. The Map Guide to US Federal Censuses 1790-1920, addresses the above problem.
Packets are available for maps of individual states, as found in the above book.
Census records after 1920 are closed for 72 years due to rights of privacy. The 1930 and later censuses, cannot be freely accessed by the public. The 1890 census was destroyed by a fire in Washington, DC 13. All census records from 1790-1920 are available on microfilm. All of these microfilms are available in your local genealogy library.