US-led intervention in Iraq (2014–2021) in the context of "2017 Western Iraq campaign"

Many states began to intervene against the Islamic State, in both the Syrian civil war and the War in Iraq (2013–2017), in response to its rapid territorial gains from its 2014 invasion of Iraq, universally condemned executions, human rights abuses and the fear of further spillovers of the Syrian civil war. In later years, there were also minor interventions by some states against IS-affiliated groups in Nigeria and Libya. All these efforts significantly degraded the Islamic State's capabilities by around 2019–2020. While moderate fighting continues in Syria, as of 2025, IS has been contained to a small area and force capability.

In mid-June 2014, Iran, according to American and British information, started flying drones over Iraq, and, according to Reuters, Iranian soldiers were in Iraq fighting IS. Simultaneously, the United States ordered a small number of troops to Iraq and started flying crewed aircraft over Iraq. In July 2014, according to the International Institute for Strategic Studies, Iran sent Sukhoi Su-25 aircraft to Iraq, and Hezbollah purportedly sent trainers and advisers to Iraq in order to help Shia militias to monitor IS's movements. In August 2014, the US and Iran separately began a campaign of airstrikes on IS targets in Iraq. Since then, fourteen countries in a US-led coalition have also executed airstrikes on IS in Iraq and in Syria. Starting from September 2014, United States began closely co-operating with Saudi Arabia and Jordan to wage a co-ordinated aerial bombing campaign against IS targets across Iraq and Syria.

Combined Joint Task Force – Operation Inherent Resolve (CJTF–OIR) is a joint task force established by a U.S.-led international coalition against the Islamic State. Its stated aim is to "degrade and destroy" the Islamic State. Led by United States Army Central (ARCENT), it is composed of military forces and personnel from over 30 countries.

Formed in October 2014 by United States Central Command, CJTF-OIR was intended to replace the ad hoc arrangements that had been established to coordinate operations against ISIL, following its rapid gains in Iraq in June. Operation Inherent Resolve included the US-led intervention in Iraq (2014–2021) and the American-led intervention in the Syrian Civil War. The current commander of the coalition is U.S. Army Brigadier General Kevin J. Lambert and the current Command Senior Enlisted Leader is U.S. Army Command Sergeant Major Robert M. Preusser Jr.

The Iraqi conflict is a series of violent events that began with the 2003 American-led invasion of Iraq and deposition of Iraqi president Saddam Hussein, followed by a series of conflicts including the protracted Iraq War (2003–2011), the Iraqi insurgency (2011–2013), the War in Iraq (2013–2017), and most recently, the small-scale Islamic State insurgency in 4 provinces located in Northern Iraq since 2017.

In the ensuing 2003–2011 Iraq War, the Multi-National Force (MNF–I) led by the United States helped to establish a Shia-dominated federal government, which was soon opposed by an Iraqi insurgency. Insurgent groups mostly fought the new government and MNF-I, but also each other, mostly along sectarian lines between Shias and Sunnis. In 2011, the MNF–I withdrew from Iraq, leading to renewed sectarian violence and enabling the emergence of the Islamic State (IS). The renewed war drew an American-led intervention in 2014. The most recent war in the country came to a close in 2017 as the Iraqi government and its allies largely defeated the IS, which was followed by a low-level IS insurgency in certain rural northern parts of the country.

In June 2014, the Islamic State (also known as ISIS or ISIL), which had controlled a large portion of Northeastern Syria at that time during the Syrian civil war, launched a full-scale invasion of Iraq, capturing a large swath of territory extending all the way from the Iraq–Syria border to the outskirts of the Iraqi capital city of Baghdad. The invasion came after months of clashes in Anbar province, where tribal groups, and some extremist factions—which had pledged allegiance to ISIL—had been fighting Iraqi government forces in the cities of Fallujah and Ramadi following a series of anti-government protests. The offensive led to the occupation of 40% of Iraq’s territory by the Islamic State, the collapse of several elements of the then-corrupt Iraqi Army and the genocides and mass killings of various religious groups, such as the Yazidis, Christians and Shia Muslims (who form a majority in the country). This event led to the intervention of Iran and the United States in assisting Iraq in its conflict with the Islamic State, with the latter providing assistance to both Iraqi and Kurdish forces.

The Islamic State of Iraq and the Levant and its allies captured several cities and surrounding territory, beginning with an attack on Samarra on 4 June, followed by the seizure of Mosul on 10 June, and Tikrit on 11 June. As Iraqi government forces fled south on 13 June, Kurdistan Regional Government force's took control of the oil hub of Kirkuk, part of the disputed territories of Northern Iraq.