The 1900 U.S. Census documents are available to search for free online. The census questions provide a great deal of information for family historians and genealogists.
Source: Szucs, Loretto Dennis, "Research in Census Records."
In The Source: A Guidebook of American Genealogy, ed. Loretto Dennis Szucs and Sandra Hargreaves Luebking (Salt Lake City: Ancestry, 1997).