Finding Government Information 

ASIL Guide to Electronic Resources for International Law - American Society of International Law - features an introduction to treaty research and treaties and information available on the Internet

Foreign Relations of the United States - "Series presents the official documentary historical record of major U.S. foreign policy decisions and significant diplomatic activity." the series began in 1861 and now has more than 350 individual volumes. "Foreign Relations 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." Online here from the Truman administration through the  Nixon-Ford Administrations.  From the U.S. State Department. Many volumes are available in print at the Stewart Library - Government Documents, lower level North, S 1.1.

Foreign Relations of the United States   - U.S. Department of State - Office of the Historian.  Browse by volumes, themes, such as United Nations, oceans, U.S. China Trade, or by Administration (Truman - Nixon-Ford)

Foreign Relations of the United States   - University of Wisconsin Digital Collections - Incomplete run from 1861-1960. 

Papers Relating to the Foreign Relations of the United States  Avalon Project - Yale Law School

Research Guide - Treaties - Duke Law Library

Researching U.S. Treaties and Agreements   LLRX

Treaties - Thomas - Library of Congress.  Search from 90th Congress, type of treaty and dates.

Treaties in Force  - U.S. Department of State

Treaties and Other International Agreements:  The Role of the United States Senate;  A Study

Senate's Treaty Making Powers