Up to 35 million Kurds live in the mountainous region that roughly straddles the borders of Iraq, Syria, Iran, Turkey and Armenia.
The Kurds are the fourth-largest indigenous ethnic group in the Middle East, but they never won an independent state of their own.
Some Kurdish nationalists want to create an independent nation-state consisting of some or all of the areas within the countries that have a Kurdish majority, while others want greater autonomy within the existing national boundaries.
In Iraq, the Kurds control a largely autonomous area in the country’s north, while the Kurdish rebels fighting in Syria’s civil war occupied large swaths of northern Syria when government forces loyal to strongman Bashar al Assad left to fight elsewhere in the country.
The Kurds in Syria had hoped to establish an autonomous region in those lands as part of a Syrian federation once the war had ended.
Their history of fighting ISIS dates to 2013, when the jihadi terror group targeted three Kurdish enclaves that bordered the so-called caliphate it had established in northern Syria.
ISIS launched repeated attacks until mid-2014, when it was repelled by Syrian Kurdish forces.
The ISIS advance in northern Iraq in June 2014 also drew Iraq’s Kurds into the conflict.
In response to escalating violence in 2014, a US-led coalition, which included the Kurds, launched airstrikes in northern Iraq against ISIS.
Since then, the Kurds, helped by coalition airpower, have driven ISIS out thousands of square miles of territory in Syria and taken control of hundreds of miles along the border with Turkey.