Census
What is collected? An excellent aid regarding the U.S. Census information from 1790 through 1930 is offered by Genealogy.com
Searchable collections by FamilySearch:
- Federal census for 1840, 1850, 1860, 1870, 1880, 1900, 1910, 1920, 1930, 1940
- Mortality Schedule 1850
- State census for 1855, 1865
All of the census records are available free online at Archive.org. You can read and even download the massive files.