Unpublished Federal documents are acquired, organized, and stored by the National Archives and Records Administration (NARA). The NARA, as the name suggests, is an archive, and organizes documents, like other archives, by provenance. In the case of the NARA, provenance generally means originating agency.
To identify these unpublished government documents, use NARA's catalog. Some of the documents listed in this catalog have been digitized, and are available online through links in the NARA Catalog:
NARA has also microfilmed many of its most "important" (depending on how one defines "important") document collections, and these microfilmed document collections can be identified using NARA's catalog of microfilmed documents:
NARA also has a printed version of their microfilm catalog, which some researchers find easier to use:
Some documents of the Federal Government are published by the U.S. Government Printing Office (the largest publisher in the world), and distributed to libraries through the Federal Depository Library Program. These published government documents can be identified using the Monthly Catalog of United States Government Publications and also through library catalogs.
For more help finding government documents, contact the Government Documents Librarian, Sanga Sung: firstname.lastname@example.org .
Below are digital collections of both published and unpublished government documents: