By constitutional requirement, the federal government of the United States conducts an enumeration of the nation every ten years. Since the first census in 1790, the returns from these censuses have become an invaluable source of information for genealogists and others. This collection of census records contains a vast amount of information on millions of Americans.
Although the questions asked and information provided has changed since that first census, there is some basic information provided in all indexes. The name of the head of the household is provided from the first census. In 1800, age categorization and residence was added to the other questions regarding slaves, and number of males and females. In 1820, categorization of occupation was added. In 1830, categorization of deaf, dumb, and blind persons was added. In 1850, the name, age, sex, color, place of birth, and literacy was added to the questionnaire. In 1860, the value of real estate was an added feature of the enumeration. And in 1880 the census added questions relative to marital status, and parents' place of birth.
VETERAN SCHEDULES (1840-1890)
In 1840 an enumeration of living Revolutionary War veterans was included in the census. This was a list of names recorded on the back of the original printed census forms. Beginning in 1870, the enumerators asked questions regarding Civil War veterans and lists were compiled from these records. In both cases, only the name of the veteran is available.
At the 1850 and 1860 censuses, an enumeration of slaves was performed. Full names were rarely recorded, yet each slave was numbered. Organized by owner, each person was listed with age, sex and color. With these details, along with other facts gathered outside the schedule, it is possible to locate a specific person without actually finding their name.
Despite the wealth of information available in census indexes, there are limitations. These include incomplete information, mis-transcribed information, mis-recorded information, and incorrect information. Reasons for these problems include persons who refused to answer the enumerators questions, persons who lied in answer to the enumerators questions, persons missed by the enumerators, and human error in writing down the information originally or transmitted incorrectly.
For further, more detailed, information refer to Chapter 5 (pg. 103-146) in The Source, edited by Loretto Dennis Szucs and Sandra Hargreaves Luebking, or Chapter 9 (pg. 301-352) in Printed Sources, edited by Kory L. Meyerink.
All available U.S. federal census schedules, from 1790 to 1930, have been microfilmed and are available here at Ancestry.com, at the National Archives in Washington, D.C., at the National Archives' regional archives in twelve states, at the LDS Family History Library and LDS family history centers throughout North America, at many large libraries, and through microfilm lending companies. Some state and local agencies may have census schedules only for the state or area served.