Member states of the Organisation of Islamic Cooperation

The Organisation of Islamic Cooperation founded in 1969 has 57 members, 56 of which are also member states of the United Nations. Some, especially in West Africa, are – though with large Muslim populations – not necessarily Muslim majority countries. A few countries with significant Muslim populations, such as Russia and Thailand, sit as Observer States, while others, such as India and Ethiopia, are not members.

The collective population of OIC member states is over 1.6 billion as of 2011.

Syria has one self-declared autonomous region:

Suspended in August 2012 during the Syrian civil war.

Transcontinental country in Europe and Asia, classified as West Asian countries by the United Nations Statistics Division:  Azerbaijan

and Brčko District, a self-governing administrative unit.
Was given an invitation in 2013 by the OIC to join as a full member.

Russia effectively administers Crimea as two federal subjects:

The Treaty on Accession of the Republic of Crimea to Russia was signed between representatives of the Republic of Crimea (including Sevastopol, with which the rest of Crimea briefly unified) and the Russian Federation on 18 March 2014 to lay out terms for the immediate admission of the Republic of Crimea and Sevastopol as federal subjects of Russia and part of the Russian Federation. It was ratified by the Federal Assembly by March 21.

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