Both the US Census Department and HathiTrust provide digitized historical copies of the United States Census - though not all portions - and not for all years.
The US Census provides a more organized collection of all the past copies of the census - and a better description of what's in them. On the other hand, once you find copies of the census from HathiTrust - they can be more easily word-searched.
Most of the census' population schedules were badly damaged by a fire in the Commerce Department Building in January 1921. For more information about the fire, the National Archives published an article, "First in the Path of the Firemen: The Fate of the 1890 Population Census," in its Spring 1996 Prologue.
"The Census of Agriculture, taken every five years, is a complete count of U.S. farms and ranches and the people who operate them. The Census looks at land use and ownership, operator characteristics, production practices, income and expenditures, and many other areas. The first agriculture Census was taken in 1840 as part of the Sixth Decennial Census of Population. For 156 years (1840 – 1996) the U.S. Department of Commerce, Bureau of the Census was responsible for collecting data for the Census of Agriculture. In 1997, responsibility for conducting the Census of Agriculture transferred to the U.S. Department of Agriculture’s National Agricultural Statistics Service (NASS)."
"The Statistical Abstract of the United States, published from 1878 to 2012, is the authoritative and comprehensive summary of statistics on the social, political, and economic organization of the United States. It is designed to serve as a convenient volume for statistical reference, and as a guide to other statistical publications and sources both in print and on the Web." --- U.S. Census Bureau