The Islamic State of Iraq and the Levant (ISIL //), also known as the Islamic State of Iraq and Syria or Islamic State of Iraq and al-Sham (ISIS //), Islamic State (IS) and by its Arabic language acronym Daesh (Arabic: داعش dāʿish, IPA: ), is a Salafi jihadist terrorist organisation and former unrecognised proto-state that follows a fundamentalist, Salafi/Wahhabi doctrine of Sunni Islam. ISIL gained global prominence in early 2014 when it drove Iraqi government forces out of key cities in its Western Iraq offensive, followed by its capture of Mosul and the Sinjar massacre.
The group has been designated a terrorist organisation by the United Nations and many individual countries. ISIL is widely known for its videos of beheadings and other types of executions of both soldiers and civilians, including journalists and aid workers, and its destruction of cultural heritage sites. The United Nations holds ISIL responsible for human rights abuses and war crimes. ISIL also committed ethnic cleansing on an historic scale in northern Iraq.
ISIL originated as Jama'at al-Tawhid wal-Jihad in 1999, which pledged allegiance to al-Qaeda and participated in the Iraqi insurgency following the 2003 invasion of Iraq by Western forces at the behest of the United States. The group proclaimed itself a worldwide caliphate and began referring to itself as the Islamic State (الدولة الإسلامية ad-Dawlah al-Islāmiyah) or IS in June 2014. As a caliphate, it claims religious, political and military authority over all Muslims worldwide. Its adoption of the name Islamic State and its idea of a caliphate have been widely criticised, with the United Nations, various governments and mainstream Muslim groups rejecting its statehood.
In Syria, the group conducted ground attacks on both government forces and opposition factions and by December 2015 it held a large area in western Iraq and eastern Syria, containing an estimated 2.8 to 8 million people, where it enforced its interpretation of sharia law. ISIL is believed to be operational in 18 countries across the world, including Afghanistan and Pakistan, with "aspiring branches" in Mali, Egypt, Somalia, Bangladesh, Indonesia and the Philippines. In 2015, ISIL was estimated to have an annual budget of more than US$1 billion and a force of more than 30,000 fighters.
In July 2017, the group lost control of its largest city, Mosul, to the Iraqi army. Following this major defeat, ISIL continued to lose territory to the various states and other military forces allied against it, until it controlled no meaningful territory by November 2017. U.S. military officials and simultaneous military analyses reported in December 2017 that the group retained a mere 2 percent of the territory they had previously held. On 10 December 2017, Iraq's Prime Minister Haider al-Abadi said that Iraqi forces had driven the last remnants of Islamic State from the country, three years after the militant group captured about a third of Iraq's territory.
In April 2013, having expanded into Syria, the group adopted the name ad-Dawlah al-Islāmiyah fī 'l-ʿIrāq wa-sh-Shām (الدولة الإسلامية في العراق والشام). As al-Shām is a region often compared with the Levant or Greater Syria, the group's name has been variously translated as "Islamic State of Iraq and al-Sham", "Islamic State of Iraq and Syria" (both abbreviated as ISIS), or "Islamic State of Iraq and the Levant" (abbreviated as ISIL).