Foreign Relations of the United States (FRUS) is the official historical record of U.S. foreign policy decisions that have been declassified and made available in this set. FRUS is produced by the U.S. State Department's Office of this Historian. Types of documents in FRUS include correspondence, text of treaties, Presidential and other messages. FRUS is great trove of primary source material for various topics.
There are several different tools that provide online access to FRUS. There are gaps in various tools be sure to check the dates of coverage with each search.
The Blume Library and Law Library have some copies in print. See the Library Catalog to find these items.
Other FRUS Sources
Some noteworthy categories, that may not be found in Hein Online, include: Executive Agency Publications, Economic Report of the President, and daily Congressional Reports.