AMDOCS: Documents for the Study of American History (http://www.vlib.us/amdocs/) American History primary documents
The American Presidency Project (https://www.presidency.ucsb.edu/) Public papers of the presidents
National Archives and Records Adminstration An independent feral agency that manages all federal recors, including The Declaration of Independence the Constitution of the United States, and the Bill of Right
National Security Archive A library and archive of declassified US documents obtained through the Freedom of Information Act, run by The George Washington University.
US Bilateral Relations Fact Sheets Information from the State Department on US relations with 200 separate countries.
State Department Freedom of Information Links to State Department records and informaiton access programs.
US Census Bureau Maps, gazetteerfiles, an the American Community Survey, as well as statistics on income, poverty, housing, demographics, genealogy, and economics.
The World Factbook (CIA) Maps as well as information about a country's geography, people, government, economy, communications, transportation, military, and transnational issues. Includes maps of the world.