These are collections and projects which are intended to permanently preserve digital copies of Federal Government sites and publications.
If you know the URL of a particular agency, office, committee, etc., you can plug it into the Wayback Machine to view snapshots of past Web sites, some dating back to 1996.
A listing of U.S. Government retrospective publication digitization efforts. As of May 2011, over 180 projects (such as the Economic Report of the President, 1947-date) are available.
The U.S. National Archives' "captures" (copies) "one-time snapshot of agency public web sites" in an effort to preserve them as historical resources. As of May 2011, this collection includes Federal agencies as of late 2004 and the 109th, 110th, and 111th Congresses (2006-2010).
Preserves data from over 3,000 U.S. Government Web sites during the transition between the administrations of President George W. Bush and President Barack Obama (September 2008-November 2009).
Permanent access to defunct Federal Government agencies and commissions and their publications. Joint project of the U.S. Government Printing Office and the Univesity of North Texas.
Multi-institutional p roject to "identify, digitize, archive, and provide access to federal technical reports issued prior to 1975."