# Islamic State (الدولة الإسلامية)
**The Islamic State** (الدولة الإسلامية, ad-Dawla al-Islamiyya), also known as ISIS, ISIL, or Daesh, is a militant Sunni jihadist movement that grew out of al-Qaeda in Iraq, proclaimed a caliphate over parts of Iraq and Syria in June 2014, and lost its last territorial stronghold at Baghouz in March 2019, since which it has operated as a decentralized insurgent and terrorist network with affiliates concentrated in Africa and [South Asia](https://www.edgepedia.org/south-asia).[1](https://www.wilsoncenter.org/article/timeline-the-rise-spread-and-fall-the-islamic-state) • [2](https://www.cfr.org/backgrounders/islamic-state)
| Key fact | Detail |
|---|---|
| Origins | Abu Musab al-Zarqawi's Jama'at al-Tawhid wa al-Jihad pledged allegiance to al-Qaeda in September 2004, becoming al-Qaeda in Iraq (AQI)[3](https://www.brookings.edu/articles/key-dates-in-the-rise-of-the-islamic-state-isis/) |
| Caliphate declared | June 29, 2014, by leader Abu Bakr al-Baghdadi, renaming the group the Islamic State[3](https://www.brookings.edu/articles/key-dates-in-the-rise-of-the-islamic-state-isis/) |
| Territorial peak | About one third of Syria and 40 percent of Iraq; in late 2014 its territory equaled the size of Great Britain[1](https://www.wilsoncenter.org/article/timeline-the-rise-spread-and-fall-the-islamic-state) • [4](https://time.com/5506007/trump-isis-victory-islamic-state/) |
| Financing | Oil sales netted an estimated $1 million to $3 million a day at its height, alongside extortion, ransoms, and antiquities trafficking[2](https://www.cfr.org/backgrounders/islamic-state) |
| Territorial defeat | A U.S.-led coalition began airstrikes on August 7, 2014; by December 2017 IS had lost 95 percent of its territory, and Baghouz fell on March 23, 2019[1](https://www.wilsoncenter.org/article/timeline-the-rise-spread-and-fall-the-islamic-state) |
| Current strength | UN experts estimated 5,000 to 7,000 members across Iraq and Syria in 2023; a 2025 report put the number in Syria at about 2,500[5](https://apnews.com/article/875d5ee8a0978f3b28aeec210b33cd5f) • [6](https://www.lemonde.fr/en/international/article/2025/12/15/syria-jihadist-infiltration-in-security-forces-poses-challenge_6748506_4.html) |
| Leadership | Abu Bakr al-Baghdadi, self-proclaimed caliph, killed in a U.S. raid in northern Syria on October 26, 2019[1](https://www.wilsoncenter.org/article/timeline-the-rise-spread-and-fall-the-islamic-state) |
## Origins: from Zarqawi to the Islamic State of Iraq
The movement traces its lineage to the aftermath of the 2003 U.S. invasion of Iraq. [Abu Musab al-Zarqawi](https://www.edgepedia.org/abu-musab-al-zarqawi), a Jordanian militant released from prison in 1999 after serving part of a 15-year sentence, moved to Afghanistan, built a training camp there with permission from al-Qaeda and the Taliban, and formed the group known as Jama'at al-Tawhid wa al-Jihad (JTWJ). After the U.S. invasion of Iraq on March 20, 2003, his forces launched car bombings in Baghdad and Najaf targeting the United States, the international community, and the Shia, whom Zarqawi viewed as the chief threat to Sunni power in Iraq.[3](https://www.brookings.edu/articles/key-dates-in-the-rise-of-the-islamic-state-isis/)
In September 2004 Zarqawi pledged allegiance to al-Qaeda and [Osama bin Laden](https://www.edgepedia.org/osama-bin-laden), and the group became al-Qaeda in Iraq (AQI). The relationship was tense from the start: in 2005, bin Laden's deputy [Ayman al-Zawahiri](https://www.edgepedia.org/ayman-al-zawahiri) castigated Zarqawi for indiscriminate attacks on civilians, particularly Shias, arguing that such violence would alienate Sunnis from the project.[3](https://www.brookings.edu/articles/key-dates-in-the-rise-of-the-islamic-state-isis/) • [2](https://www.cfr.org/backgrounders/islamic-state) AQI nevertheless mounted a broad insurgency and for several years controlled some of the Sunni-populated parts of Iraq.[7](https://www.brookings.edu/articles/isis-vs-al-qaeda-jihadisms-global-civil-war/)
Zarqawi was killed in a U.S. airstrike on June 7, 2006. Four months later, on October 15, 2006, his successors announced the establishment of the Islamic State in Iraq (ISI), with [Abu Omar al-Baghdadi](https://www.edgepedia.org/abu-omar-al-baghdadi) as its leader.[1](https://www.wilsoncenter.org/article/timeline-the-rise-spread-and-fall-the-islamic-state) The group suffered heavily during the U.S. troop surge of 2007 and the Sunni Awakening councils: by early 2008, 2,400 ISI members had been killed and 8,800 captured out of a previous membership of about 15,000.[1](https://www.wilsoncenter.org/article/timeline-the-rise-spread-and-fall-the-islamic-state) In April 2010, a joint U.S.-Iraqi operation killed Abu Omar al-Baghdadi and his deputy Abu Ayyub al-Masri, and [Abu Bakr al-Baghdadi](https://www.edgepedia.org/abu-bakr-al-baghdadi) became ISI's new leader.[3](https://www.brookings.edu/articles/key-dates-in-the-rise-of-the-islamic-state-isis/) • [1](https://www.wilsoncenter.org/article/timeline-the-rise-spread-and-fall-the-islamic-state)
## Rivalry with al-Qaeda
The two organizations follow discernibly different strategies. Al-Qaeda pursues a "far enemy" strategy, plotting attacks on the United States and its Western allies to push them out of the [Muslim world](https://www.edgepedia.org/muslim-world), while the Islamic State prefers the "near enemy," targeting regional regimes, albeit at a larger territorial scale.[7](https://www.brookings.edu/articles/isis-vs-al-qaeda-jihadisms-global-civil-war/) Al-Qaeda has favored a longer game of nurturing unstable societies into hosts for an eventual Islamic state, whereas the Islamic State sought to seize and hold ground from state actors immediately.[8](https://www.brookings.edu/articles/experts-weigh-in-part-3-what-is-the-future-of-al-qaida-and-the-islamic-state/)
The formal split came through Syria. Baghdadi sent operatives to Syria in 2011, and Abu Muhammad al-Julani established the Nusra Front there in January 2012. In April 2013 Baghdadi announced that ISI had merged with the Nusra Front to form the [Islamic State of Iraq](https://www.edgepedia.org/islamic-state-of-iraq) and Syria (ISIS); Julani rejected the merger and declared allegiance to al-Qaeda, and al-Qaeda officially cut ties with ISIS on February 3, 2014.[1](https://www.wilsoncenter.org/article/timeline-the-rise-spread-and-fall-the-islamic-state) The rivalry remains active: in a May 2015 interview, the Nusra leader condemned the Islamic State as "khawarij," a heretical sect, for justifying the killing of other Muslims.[9](https://www.brookings.edu/wp-content/uploads/2016/07/Brookings-Analysis-Paper_Mara-Revkin_Web.pdf)
## The caliphate, 2014 to 2019
ISIS's expansion exploited Sunni disenfranchisement in both countries. In Iraq, Prime Minister Nouri al-Maliki's exclusion of Sunni political rivals, the collapse of the Awakening councils, and the demoralization of the Iraqi army all contributed to ISIS overrunning Mosul, Iraq's second-largest city, on June 10, 2014. In Syria, the civil war that began with the 2011 uprising gave the group space to expand.[2](https://www.cfr.org/backgrounders/islamic-state) On June 29, 2014, Baghdadi announced the establishment of a caliphate stretching from Aleppo in Syria to Diyala in Iraq and renamed the group the Islamic State.[3](https://www.brookings.edu/articles/key-dates-in-the-rise-of-the-islamic-state-isis/) • [1](https://www.wilsoncenter.org/article/timeline-the-rise-spread-and-fall-the-islamic-state)
**Governance and brutality.** Within its territory the group imposed a harsh interpretation of Islam, killing, raping, and abusing members of other faiths and targeting fellow Sunni Muslims who strayed from it. At Raqqa, its nominal capital, it established judicial, police, and economic institutions and coopted education, health, and infrastructure services. It imposed a 10 percent ʿushr tax on non-Muslim foreign traders, with lower rates of 5 percent and 2.5 percent for local non-Muslims and Muslims respectively.[2](https://www.cfr.org/backgrounders/islamic-state) • [9](https://www.brookings.edu/wp-content/uploads/2016/07/Brookings-Analysis-Paper_Mara-Revkin_Web.pdf)
**Finances.** Oil extraction was the group's largest source of income; it sold crude pumped from Iraqi and Syrian wells at below-market prices, netting an estimated $1 million to $3 million a day. Ransom payments provided upwards of $20 million in 2014, according to the U.S. Treasury, and extortion of businesses and antiquities trafficking added further revenue. U.S.-led strikes targeted this oil infrastructure from 2015.[2](https://www.cfr.org/backgrounders/islamic-state)
**The coalition campaign.** A U.S.-led coalition of some sixty countries began airstrikes against the Islamic State in Iraq on August 7, 2014, expanding to Syria the following month, and the campaign was named [Operation Inherent Resolve](https://www.edgepedia.org/operation-inherent-resolve). By December 2017 the group had lost 95 percent of its territory, including Mosul and Raqqa. Iraqi Prime Minister Haider al-Abadi declared victory over the Islamic State in Iraq on December 9, 2017.[1](https://www.wilsoncenter.org/article/timeline-the-rise-spread-and-fall-the-islamic-state) By 2017 the group had lost more than 90 percent of its territory across both countries, and the last holdout, Baghouz, fell to the [Syrian Democratic Forces](https://www.edgepedia.org/syrian-democratic-forces) on March 23, 2019, formally ending the caliphate's claim to any territory.[10](https://research.sharqforum.org/2021/04/22/islamic-state-resurgence-in-iraq-and-syria/) • [1](https://www.wilsoncenter.org/article/timeline-the-rise-spread-and-fall-the-islamic-state)
During its peak years the group also inspired or directed attacks abroad, including the [November 2015 Paris attacks](https://www.edgepedia.org/november-2015-paris-attacks) that killed 130 people, and it attracted large numbers of foreign fighters; U.S. Director of National Intelligence James Clapper estimated in February 2015 that more than 13,000 foreign fighters had joined Sunni extremist groups in Syria.[11](https://apnews.com/article/4bb6446c484737fbe9dd1b9c26a899a9) • [2](https://www.cfr.org/backgrounders/islamic-state)
## Insurgency and affiliates after 2019
The group transformed into a decentralized global network after losing its territory. UN experts assessed in 2023 that it still commanded between 5,000 and 7,000 members across Iraq and Syria, most of them fighters, and that it had deliberately reduced attacks to facilitate recruiting and reorganization.[5](https://apnews.com/article/875d5ee8a0978f3b28aeec210b33cd5f) A 2025 report put the number of IS fighters in Syria at about 2,500, concentrated in the Badiya Desert straddling government-held and Kurdish-administered areas.[6](https://www.lemonde.fr/en/international/article/2025/12/15/syria-jihadist-infiltration-in-security-forces-poses-challenge_6748506_4.html)
The geographic center of its activity has shifted to Africa. UN briefings identify the Islamic State West Africa Province (ISWAP), estimated at 8,000 to 12,000 fighters, as the most active affiliate globally, and the Islamic State in the Greater Sahara (ISGS) as consolidating in the Niger-Nigeria border area.[12](https://www.youtube.com/watch?v=eiD6-ZRm5iM) The Afghan affiliate, Islamic State Khorasan Province (IS-K), claimed the March 2024 attack on a Moscow concert hall, illustrating a regionalization strategy that has followed the loss of the Iraq-Syria base.[13](https://www.lemonde.fr/en/international/article/2024/03/25/moscow-attack-how-central-asia-became-the-islamic-state-organization-s-new-foothold_6651043_4.html)
**Detainee crisis.** Roughly 11,000 suspected IS fighters were held by Kurdish forces in northeast Syria in early 2024, alongside about 48,500 people with presumed or family links to the group in the closed camps of Al-Hawl and Roj, two-thirds of them children.[14](https://www.lemonde.fr/en/international/article/2024/03/31/is-rebuilds-its-networks-in-syria-carrying-out-deadly-ambushes_6666928_4.html) After fighting broke out in January 2026 between Syrian government forces and the Kurdish-led Syrian Democratic Forces, the U.S. military completed the transfer of some 5,700 prisoners with alleged IS ties from northeast Syria to detention facilities in Iraq, and Iraq has since rejected Syria's request to repatriate about 4,000 Syrian detainees for trial there.[15](https://apnews.com/article/d9e4171da3346fcaf092fa583bebf8c5)
## How the Islamic State compares with its parent
The Islamic State's defining departure from al-Qaeda lies in what it built. While al-Qaeda functioned as an elite, top-down, members-only organization in which plots required headquarters' approval, the Islamic State combined top-down military command with a looser "movement" model of terror, broadcasting appeals for anyone, anywhere, to strike in its name.[16](https://time.com/4393398/isis-terror-attacks-turkey-iraq-bangladesh/) It also ran an actual proto-state: a bureaucratic organization that controlled thousands of square miles, governed millions of people, and imposed taxation and courts, in contrast to al-Qaeda affiliates, which generally seek to offer an alternative local governance system without holding an explicit caliphate.[3](https://www.brookings.edu/articles/key-dates-in-the-rise-of-the-islamic-state-isis/) • [17](https://www.iiss.org/publications/armed-conflict-survey/2023/from-global-jihad-to-local-insurgencies/) That state-building project drew the sustained conventional military response that a clandestine terrorist network never invited, and its collapse in 2019 marks the central difference between the two groups' trajectories since.[1](https://www.wilsoncenter.org/article/timeline-the-rise-spread-and-fall-the-islamic-state)
## References
1. [Timeline: the Rise, Spread, and Fall of the Islamic State, Wilson Center](https://www.wilsoncenter.org/article/timeline-the-rise-spread-and-fall-the-islamic-state)
2. [The Islamic State, Council on Foreign Relations Backgrounder](https://www.cfr.org/backgrounders/islamic-state)
3. [Key Dates in the Rise of the Islamic State (ISIS), Brookings Institution](https://www.brookings.edu/articles/key-dates-in-the-rise-of-the-islamic-state-isis/)
4. [ISIS Is Still Active in Iraq, Syria and Beyond. This Is What the Threat Looks Like Now, TIME](https://time.com/5506007/trump-isis-victory-islamic-state/)
5. [Islamic State group still has thousands in Syria and Iraq and poses Afghan threat, UN experts say, Associated Press](https://apnews.com/article/875d5ee8a0978f3b28aeec210b33cd5f)
6. [Syria: Jihadist infiltration in security forces poses challenge, Le Monde](https://www.lemonde.fr/en/international/article/2025/12/15/syria-jihadist-infiltration-in-security-forces-poses-challenge_6748506_4.html)
7. [ISIS vs. Al Qaeda: Jihadism's global civil war, Brookings Institution](https://www.brookings.edu/articles/isis-vs-al-qaeda-jihadisms-global-civil-war/)
8. [Experts Weigh In (part 3): What is the future of al-Qaida and the Islamic State?, Brookings Institution](https://www.brookings.edu/articles/experts-weigh-in-part-3-what-is-the-future-of-al-qaida-and-the-islamic-state/)
9. [The legal foundations of the Islamic State, Mara Revkin, Brookings Institution](https://www.brookings.edu/wp-content/uploads/2016/07/Brookings-Analysis-Paper_Mara-Revkin_Web.pdf)
10. [Examining the Islamic State Resurgence in Iraq and Syria, Al Sharq Strategic Research](https://research.sharqforum.org/2021/04/22/islamic-state-resurgence-in-iraq-and-syria/)
11. [What is the Islamic State group and what attacks has it inspired?, Associated Press](https://apnews.com/article/4bb6446c484737fbe9dd1b9c26a899a9)
12. [Da'esh remains resilient amid global pressure, Africa is now epicentre of activity, United Nations](https://www.youtube.com/watch?v=eiD6-ZRm5iM)
13. [Moscow attack: How Central Asia became the Islamic State organization's new foothold, Le Monde](https://www.lemonde.fr/en/international/article/2024/03/25/moscow-attack-how-central-asia-became-the-islamic-state-organization-s-new-foothold_6651043_4.html)
14. [IS rebuilds its networks in Syria, carrying out deadly ambushes, Le Monde](https://www.lemonde.fr/en/international/article/2024/03/31/is-rebuilds-its-networks-in-syria-carrying-out-deadly-ambushes_6666928_4.html)
15. [Iraq rejects Syrian request to repatriate 4,000 suspected IS detainees, official says, Associated Press](https://apnews.com/article/d9e4171da3346fcaf092fa583bebf8c5)
16. [The Wave of ISIS Terror Attacks Is a Mark of Weakness-Not Strength, TIME](https://time.com/4393398/isis-terror-attacks-turkey-iraq-bangladesh/)
17. [Armed Conflict Survey 2023: From Global Jihad to Local Insurgencies, IISS](https://www.iiss.org/publications/armed-conflict-survey/2023/from-global-jihad-to-local-insurgencies/)
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*Topic: Encyclopedia › Society and history › Conflict and security › Wars, campaigns, and incidents › Civil wars, rebellions, and uprisings › Insurgencies and guerrilla conflicts › Jihadist insurgencies*
*Initially written Sep 17, 2026 · Reviewed: Sep 19, 2026; Sep 30, 2026; Oct 25, 2026 · Edited: Sep 18, 2026; Sep 19, 2026; Oct 25, 2026 · Last review: Oct 25, 2026*
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