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 about the specific questions asked in each census:
To protect the privacy of the individuals whose names appear in each schedule, population schedules are restricted for seventy-two years after the census is taken and are not available to researchers during that time.
All of the National Archives microfilm publications relating to Pennsylvania, including the federal population census 1790-1940 (except for 1890 which was destroyed by fire in 1921) are in the State Library's collection. Except for 1870 there is a name index for each of the Pennsylvania population census schedules. Book indexes list the heads of families from 1790 through 1860. For 1870, only portions of the Pennsylvania census have been indexed. The 1880 Soundex Index includes only households with children aged ten years and younger but the 1900 Soundex Index and the 1910 Miracode Index include all heads of families.
The 1790-1940 censuses may also be searched remotely through the National Archives catalog or through sites such as Ancestry.com, Fold3.com and FamilySearch.org.
Soundex is a coded surname index that groups names based on sound rather than spelling. This enables researchers to locate information on surnames that may have different spellings.