When searching for information on treaties to which the United States is not a party, the following sources should be consulted:
Clive Parry, ed. Consolidated Treaty Series (JX120 P35, Level 4)
This is a collection of world treaties, with limited annotations, in their original languages and existing translations in English or French from 1648 to the beginning of the League of Nations Treaty Series (approximately 1918 to 1920). Also available on HeinOnline (subscription access)
League of Nations Treaty Series (JX170 L4, Level 4)
Treaties of member and nonmember nations registered with the Secretariat from 1920 to 1946. Also available on HeinOnline (subscription access)
United Nations Treaty Series (U.N.T.S.) (JX170 U35, Level 4)
Beginning with 1946, this set contains the text of all treaties registered with the Secretariat by its member states, or filed and recorded by nonmember states or international organizations. It is not as comprehensive as the United Nations intended, especially for bilateral treaties. Cumulative indexes are published for every 50 volumes of the Series. The Series is currently published with a lag time of about 10 years and the Index with a lag time of about 15 years. This publication is available in the United Nations Treaty Database: http://treaties.un.org/Pages/UNTSOnline.aspx?id=1 Also available on HeinOnline (subscription access).
United Nations Office of Legal Affairs. Multilateral Treaties Deposited with the Secretary-General (JX1977, Level 4)
Since 1968, this yearly publication covers all multilateral treaties that have been concluded under the auspices of the United Nations and that have been deposited with the Secretary-General. An electronic version of this title is available through the United Nations Treaty Collection database. Also available on HeinOnline (subscription access).