Federation of American Scientists http://www.fas.org contains a treasure trove of intelligence assessments and studies useful to students interested in seeing actual intelligence products.

CIA http://www.cia.gov includes the Center for the Study of Intelligence, where the CIA’s official ‘Studies’ journal is available, along with many other descriptions of the intelligence process and products.

The Office of the Director of National Intelligence http://www.odni.gov houses official press releases, statements, and directives; it also contains unclassified national intelligence estimates and other community products like the Global Trends series.

Central Intelligence Agency World Factbook https://www.cia.gov/library/publications/the-world-factbook houses the voluminous CIA World Factbook that catalogues the key facts regarding 267 world entities, including their demographics, economy, history, political structure, and other pertinent characteristics.