POPULATION CENSUS RECORDS
Beginning in 1790 a census of the population of the United States has been taken every ten years by the federal government for the purpose of apportioning representatives to the lower house of Congress. No other single group of source records provides more information about persons who lived in this country during the nineteenth century. From census records you can learn specific information about a family but the primary use of census information is to serve as a connector to other records . When you know the place of residence of a family, you then know where to look for other records such as deeds, marriages, births, deaths and wills.
For more information, the State Library of Pennsylvania maintains a guide to Genealogy Research and the U.S. Census.