As classified documents are released to the public, they may appear in any of several databases or web sites. As no single site or database provides complete coverage, you are advised to check each of these resources for a particular document or topic.
The Foreign Relations of the United States series is the official documentary historical record of major U.S. foreign policy decisions that have been declassified and edited for publication. The series, which is produced by the State Department's Office of the Historian, began in 1861 and now comprises more than 350 individual volumes. The volumes published over the last two decades increasingly contain declassified records from all the foreign affairs agencies.
FRUS volumes contain documents from Presidential libraries, Departments of State and Defense, National Security Council, Central Intelligence Agency, Agency for International Development, and other foreign affairs agencies as well as the private papers of individuals involved in formulating U.S. foreign policy. In general, the editors choose documentation that illuminates policy formulation and major aspects and repercussions of its execution. Volumes published over the past few years have expanded the scope of the series in two important ways: first by including documents from a wider range of government agencies, particularly those involved with intelligence activity and covert actions, and second by including transcripts prepared from Presidential tape recordings.
The University of Wisconsin-Madison Libraries provide access to digitized editions of the FRUS volumes from 1861-1960, with browsing and searching options. See the State Department website for volumes covering the administrations of Presidents Truman (1945-1952), Eisenhower (1953-1960), Kennedy (1961-1963), Johnson (1964-1968), Nixon (1969-1974), Ford (1974-1976), Carter (1977-1980), and Reagan (1981-1988). Volumes in the series since 1952 are organized chronologically according to Presidential administrations, and geographically and topically within each subseries.
Many records and papers produced by agencies never get released. They are not actually "classified," but are considered internal departmental documents and are therefore not published. Records like these, as well as other published and classified documents, eventually end up at NARA.
Although NARA puts select material online, most material related to foreign relations will either be on microfilm or only available at the National Archives. There are two main tools to assist you in finding out where records of interest may be located.
This reference source provides general descriptions of the Record Group collections held by the National Archives. Knowing what record group and section your material is likely to be in will be helpful when visiting the archives or when trying to locate relevant microfilm. This guide also indicates which branch of the Archives holds the materials in specific record groups. The Guide is also available in hard copy at Geisel Library, call number U.S. Docs Ref AE 1.108: G94 v. 1-3.
This catalog allows you to search by keyword, record group and more to see if there are records in your area of interest that have been microfilmed. The catalog also often includes pdf guides to microfilm sets, allowing you to explore content more thoroughly. If you know what is contained in specific rolls, you can often request only a couple of microfilm rolls from a set rather than requesting the entire set.