The recently digitized U.S. Congressional Serial Set (1817-1980) is a major primary source for historical government information.
It includes nearly all information written by and for the US Congress from 1817 to 1980, from treaties to impeachment materials to presidential messages, not to mention committee reports and journals.
If you are researching the United States government during the period covered by this set, this should be a significant resource for you.
Reproduced from http://www.williamcronon.net April 8, 2009.
The National Archives, which keep official records for the United States on things as diverse as military service records and the Constitution, has a wonderful digitized collection of historical documents. The documents include the Declaration of Independence and Bill of Rights, but also the Emancipation Proclamation, the Social Security Act, and Brown v. Board of Education.>
The world of historic government documents--not to mention documents about the government published by other sources--can sometimes seem too big to make sense of.
Here are two ways to combat confusion:
Contact a librarian! LMU librarians are here to help, and there's help available 24/7.
You can also look at this useful outline of how to find government information, organized by a graduate school seminar at U-Wisconsin, Madison and aimed specifically at other college students.
Historical government information has not all been digitized. There is a wealth of information that remain on the library shelves. The US Census, especially, still has a great deal of essential material only in print.
The US Census is accessible only through print materials for any census prior to 1990, though there are some un-official online resources. The University of Virginia has an online historical census browser that covers the years 1790-1960, accessible here. If you're looking for the print versions of a particular census, search the LMU catalog for "Census."
There is also a number of secondary source material that take data from the census and analyze it for trends and theories. See below for a selection of secondary sources available from the LMU library.