International law - treaties - Law (UK, EU and International)

General treaty collections

AVALON Project
Collection of historical documents, including treaties, from 4000BC onwards.
WorldLII Treaties and International Agreements
Treaties and agreements grouped by country, by subject, by international organizations & bodies and by multi-national collections.

Regional treaty collections

African Union
Treaties, conventions, protocols and charters concluded by the Organisation of African Unity / African Union.
Council of Europe Treaty Office
Council of Europe treaties, explanatory reports and status information.
European Union Treaties
European Union treaties are binding agreements between EU member countries. EUR-Lex contains the founding, amending and accession treaties, as well as some protocols.
European Treaties Office
Bilateral and multilateral treaties or agreements concluded by the European Union. This does not include the founding treaties or other agreements concluded between the member states of the EU.
Organization of American States
Multilateral treaties and bilateral agreements concluded by the Organization of American States.

What is a treaty?

The Vienna Convention on the Law of Treaties 1969, art 2(1a) defines a treaty as "an international agreement concluded between States in written form and governed by international law, whether embodied in a single instrument or in two or more related instruments and whatever its particular designation...".

How do I find a treaty?

Flare Index to Treaties is an excellent search tool for finding multilateral and selected bilateral treaties. It contains details of treaties from 1353 onwards, with links to full text where available.

United Nations treaties

"Every treaty and every international agreement entered into by any Member of the United Nations...shall as soon as possible be registered with the Secretariat and published by it" (Charter of the United Nations, art 102(1)).

United Nations Treaty Collection

How to find Referencing Information on the UN Treaty Collection Website
This quick guide shows how to use the UN Treaty Collection website to easily find all the information needed for your reference. This is especially helpful if all the information is not displayed in the document itself.

United Nations Treaty Series (UNTS)
Treaties and international agreements registered with the United Nations from 1946 onwards.
League of Nations Treaty Series (LNTS)
Treaties and subsequent treaty actions registered with the League of Nations from 1920-1944.
Multilateral Treaties Deposited with the Secretary-General (MTDSG)
Information on the status of around 500 treaties deposited with the Secretary-General of the United Nations.
Glossary
Explains the meaning of terms used in treaties.
Treaty Handbook
Guide on how treaties are deposited and registered with the United Nations.

National treaty collections

UK Treaties
Links to UK treaty collections and guidance on UK treaty practice from the Foreign & Commonwealth Office (FCO).

For other jurisdictions, see WorldLII 'Treaties and International Agreements by Country'.

Law (UK, EU and International): International law - treaties