Indices and guides used to locate and determine the status of treaties to which the United States is a party are listed in the Mabie Research Guide for U.S. Treaties and International Agreements. If you do not find the treaty you want listed in any of those guides, use the following to locate and determine the status of treaties to which the United States is not a party:
Multilateral Treaties Deposited with the Secretary General
Law Stacks, Second Floor JZ5105 ST/LEG/SER.E, 1981 --
Law Stacks, Second Floor JZ5105 ST/LEG/SER.D, 1969 - 1980
Also available online as part of the United Nations Treaty Collection. Some recent editions are available as part of the Hein Online United Nations Law Collection.
The Electronic Information System for International Law (EISIL) is a searchable collection of online treaty texts coupled with citations to authoritative print sources.
The University of Minnesota Law Library's list of Frequently-Cited Treaties & Other International Instruments links to treaty text online when available and provides citations to authoritative print sources.
Bowman and Harris, Multilateral Treaties: Index and Current Status
Law Stacks, Second Floor KZ118 .B68 1984
with 11th supplement, 1995
Peter Rohn, World Treaty Index, 2nd ed., 1997
Law Reference KZ173 .R64
An earlier edition (1974) is available in the University Library.
World Legal Information Institute (WorldLII) International Treaties Collection
The FLARE index to Treaties
Searchable database of more than 1500 treaties.