It is known as Kurdistan a region in the Middle East where Kurds make up the majority or a significant share of the population. No universally accepted and defined borders for that territory exist, even in places where Kurds have established their own systems of self-government.
Kurdistan spans an area straddling two major mountain ranges: the Taurus in eastern Anatolia and the Zagros, on the western limit of the Iranian plateau. According to some conceptions, the western border of Kurdistan reaches the Mediterranean Sea, while its eastern border touches the Persian Gulf. Other conceptions set the Kurdish borders tens or hundreds of kilometres away of those coasts.
In most designs, the territory of Kurdistan currently spans four sovereign countries, namely Turkey, Syria, Iran and Iraq. This four-state division, which was consolidated at the end of the First World War, has given rise to the division that Kurdish nationalism itself uses to designate the different parts of its own territory, Bakur (the Kurdish-majority region of Turkey), Rojava (of Syria), Basûr (of Iraq) and Rojhelat (of Iran).
In the two states with the largest Kurdish population (Turkey and Iran), no system of self-government with legislative powers in which the Kurds are the majority has been put in place.
The only two Kurdish-majority territories that currently have its own institutions with legislative, executive and judicial powers —and some diplomacy in the international sphere— are the Region of Kurdistan (in Iraq) and the cantons of Efrîn, Kobanê and Cizîrê integrated in the Federal Democratic System of Northern Syria.
The Kurdistan Region (name in official use) is a constitutionally recognized part of Iraq. It enjoys wide self-government, a government and a Parliament of its own, and its exclusive police and armed forces. Its territory is divided from the 1990s into two spheres of influence: the western region under the Kurdistan Democratic Party, and the eastern under the Patriotic Union of Kurdistan. The borders of the Kurdistan Region have never been definitively established. The Kurdish and Iraqi governments continue to disagree on whether areas such as Kirkuk and Sinjar should join the Kurdistan Region or not.
The Federal Democratic System of Northern Syria was unilaterally established by the PKK-linked Kurdish movement in Syria and its related organizations in 2016, bulding on the previous existence of three Kurdish-majority cantons, which were also unilaterally proclaimed in 2014: Efrîn, Kobanê and Cizîrê. The Syrian government acknowledges the existence of neither the cantons nor the Federal Democratic System, which self-styles as multiethnic and self-governing on the principles of democratic confederalism —a kind of libertarian socialism devised by PKK leader Abdullah Ocalan. The exact borders of the Federal Democratic System at any given time depend on territorial changes within the Syrian Civil War (2012-), and de facto match the front lines.
(Updated May 2017)