Treaties are the principal source of Public International Law. This page includes a summary of key information related to treaties. See the Public International Law Research Guide for more comprehensive information.
Most treaties are published in sets such as the United Nations Treaty Series (UNTS, 1946+) and the League of Nations Treaty Series (LNTS, 1920-1946). However, be aware that only treaties deposited with the UN Secretary General become part of the UNTS. Although most treaties are deposited with the UN, states are under no specific obligation to do so.
The United Nations Treaty Collection contains the following free databases:
To download a PDF copy of the treaty, as published in the UNTS, search for the treaty in the UNTC website.
Scroll down to find the desired treaty in the search results, and click on ‘See Details’.
Scroll down the table to find the ‘Volume In Pdf’ row, and click the .pdf link to save or open the file in a new window.
The Status of Treaties Deposited with the Secretary-General contains over 500 multilateral treaties deposited with the Secretary-General. This collection contains information such as the status, declarations and reservations, as well as a list of the signatory countries, including the date the treaty was accessioned, succeeded or ratified by each participating nation.
UN Audiovisual Library of International Law – Research Library: http://legal.un.org/avl/treaties.html
If you cannot find a treaty on the UN Treaty Collection (because it was never deposited with the UN), you may want to look at treaty collections maintained by states or other entities. A full list can be found in the Research Library tab.