A census is a count and description of the population of a country, state, county, or city. Census lists are also called “schedules." In the United States a nationwide census has been taken every ten years since 1790. A well-indexed census is one of the easiest ways to locate where an ancestor lived and when they lived there. You can also use censuses to:
William Thorndale, and William Dollarhide, Map Guide to U.S. Federal Censuses 1790-1920 (Baltimore: Genealogical Publ., 1987) [FHL book 973 X2th]. Shows county boundary changes in each state from 1790 to 1920, and which census areas were lost or still exist.