The U.S. Census Bureau is a well-known agency amongst genealogists. The statistics found on this website include the data derived from the information that the census takers asked our ancestors. These statistics can be useful for the family historian in placing their ancestors in a particular historical, social, or economic context.
The statistics from the decennial censuses can answer such questions as the number of people living where your ancestors lived, and prices of crops for their county or state, census of religious bodies, newspapers printed, etc. The reports from the various censuses are in the Publications section under Population and Housing. Not all reports have been scanned but more and more are being added.
Of special note is volume 8 of the 1880 Census which includes the history and present condition of the newspaper and periodical press. Information about what your ancestor may have read may be available here.
Another is A Census of Pensioners for Revolutionary Or Military Services, with their Names, Ages, and Places of Residence; part of the 1840 Census .
See the information from the 1890 Census which includes in volume 9, a report on statistics of churches to see what churches they may have attended.
Also of interest is the Statistical Abstract of the United States, which goes back to 1878 and is currently still printed and available online. You can find out number of miles of railroad in operation for the years 1830 to 1879 (in the 1880 volume). This could tell you how easy it was for your ancestor to have moved around and to where. Also in this section is the Bicentennial Edition: Historical Statistics of the United States, Colonial Times to 1970 in 2 volumes. Browsthe index or table of contents in either of these titles.
See the publications under historical census data.
The History of the Census is a new section that has just been added (5/08). It includes links to the census through the decades (back to 1790), pages on population density over time, centers of population, and statistical atlases, all of use to the fam