The largest directory of free census records available online is located at Census Finder where you can select a state, then browse each county to see what is available.
If you are new to census research, there is much information about the subject on the site also. You can learn about Federal census records as well as more obscure state census records and territorial census records.
To learn which questions were asked on each individual census year, select a year from the chart below.
Questions asked in Census Records
Where can I search for my ancestor's census records?