In our library, the source base for American empire is larger than for any other, with the possible exception of the British Empire. American empire is perhaps a little trickier to research insofar as no "American Empire" was ever declared, and yet, from the moment the "United States of America" were declared, they became a multi-national state, occupying the lands of sovereign Indigenous nations.

The sources of American empire also generally include documents of American intervention "abroad".

For journal articles on this subject, try the following article indexes:

Major collections of primary sources for researching American empire are listed on this page, with emphasis on digital collections. The list of is incomplete: it does not include, for example, any digitized book or periodical collections. For digitized collections of books, periodicals, and other sources not listed here, see the two section on American History in our Guide to Digital Collections:

Before the Presidential Records Act of 1978, all presidential papers were considered the personal property of the president, and presidents took their papers with them when they left office. The Presidential Records Act of 1978 designated any document produced during the course of the president's official duties (by both the president and his or her staff) as official, public records, and as such those documents become the property of the nation. Since 1981 each departing president has been required to deposit any such records with the National Archives and Records Administration.

The Presidential Records Act obviously does not apply to most American presidents. The papers of pre-Reagan American presidents exist in varying states of completeness, and some no longer exist at all. Many were subsequently acquired by the Library of Congress, and they have made the papers of several nineteenth century presidents available online. Some are still only available on microfilm.

Bear in mind that these "presidential papers" will include a mixture of personal and official papers.

Listed here are those presidential papers that we have in our collection here at University of Illinois. Papers of other presidents not listed might be available through interlibrary loan, and we likely have guides to those papers.

Unpublished U.S. government documents are acquired, organized, and stored by the National Archives and Records Administration (NARA).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. The government agency responsible for conducting diplomatic relations with foreign governments is the State Department. Records of the State Department can be found in Record Group 59. Learn more about the organization of State Department records (which has changed over time) here. The agency responsible for waging war against other nations has changed over time: the War Department became the Department of Defense in 1949. All these agencies fall under the Executive Branch.

Published documents are distributed to libraries through the Federal Depository Library Program, and can be identified using the Monthly Catalog of United States Government Publications (see entry under Reference Sources > Bibliographies, Catalogs, and Guides), and also through library catalogs.

Below are some collections of both published and unpublished documents:

• United States --Territorial expansion.
• United States --Territories and possessions.
• Anti-imperialist movements --United States.
• Imperialism.
• Imperialism --History --20th century.
• Hegemony --History.
• United States --Foreign relations --Philosophy.
• Latin American --Civilization --American influences.
• Colonization.
• Americanization --History --20th century.
• Civilization, modern --American influences.
• Civilization -- American influences.
• Popular culture -- American influences.
• Globalization.
• United States --Relations --Latin America.
• Philippines --Colonization --History.
• United States --Foreign relations --Philippines.
• Nationalism.

Alamancs are sources of factual information, typically issued once a year. Some titles have been published for over 100 years, making them valuable sources of historical data as well.

We've also included in this section some of the older encyclopedia sets which, while not almanacs, do share with almanacs the quality of being issued regularly over time (sometimes as often as every year).