2017 Western Iraq campaign in the context of "Al Anbar Governorate"

Operation Inherent Resolve (OIR) is the United States military's operational name for the international war against the Islamic State (IS)—a group also known as the Islamic State of Iraq and Syria (ISIS), the Islamic State of Iraq and the Levant (ISIL) or its Arab acronym "Daesh"—including both a campaign in Iraq and a campaign in Syria, with a closely related campaign in Libya. Through 18 September 2018, the U.S. Army's III Armored Corps was responsible for Combined Joint Task Force – Operation Inherent Resolve (CJTF—OIR) and were replaced by the XVIII Airborne Corps. The campaign is primarily waged by American and British forces in support of local allies, most prominently the Iraqi Security Forces (ISF) and Syrian Democratic Forces (SDF). Combat ground troops, mostly special forces, infantry, and artillery have also been deployed, especially in Iraq. Of the airstrikes, 70% have been conducted by the military of the United States, 20% by the United Kingdom, and the remaining 10% being carried out by Australia, Belgium, Canada, Denmark, France, Jordan, the Netherlands, Saudi Arabia, Turkey, and the United Arab Emirates.

According to the Pentagon, by March 2019, the day of IS's territorial defeat in Syria, CJTF—OIR and its partner forces had liberated nearly 110,000 square kilometers (42,471 square miles) of land and 7.7 million people from IS, the vast majority of the self-proclaimed caliphate's territory and subjects. By October 2017, around the time of IS's territorial defeat in Iraq, CJTF—OIR claimed that around 80,000 IS militants had been killed by it and its allies (excluding those targeted by Russian and Syrian air strikes). By the end of August 2019, it had conducted 34,573 strikes. Tens of thousands more were killed by partner forces on the ground (the SDF alone claimed to have killed 25,336 IS fighters by the end of 2017).

On 15 June 2014 U.S. President Barack Obama ordered United States forces to be dispatched in response to the Northern Iraq offensive (June 2014) of the Islamic State (ISIL), as part of Operation Inherent Resolve. At the invitation of the Iraqi government, American troops went to assess Iraqi forces and the threat posed by ISIL.

In early August 2014, ISIL began its Northern Iraq offensive. On 5 August, the United States started supplying the Kurdish Peshmerga forces with weapons. On 8 August, the United States began airstrikes against ISIL positions in Iraq. Nine other countries also launched airstrikes against ISIL, more or less in concert with Kurdish and Iraqi government ground troops. By December 2017, ISIL had no remaining territory in Iraq, following the 2017 Western Iraq campaign.

The Islamic State (IS) had its core in Iraq and Syria from 2013 to 2017 and 2019 respectively, where the proto-state controlled significant swathes of urban, rural, and desert territory, mainly in the Mesopotamian region. Today the group controls scattered pockets of land in the area, as well as other minor strongholds or underground insurgent cells in other areas, notably Afghanistan, West Africa, the Sahara, Somalia, Mozambique, and the Democratic Republic of the Congo. As of 2023, large swathes of Mali have fallen under IS control.

In early 2017, IS controlled approximately 45,377 square kilometers (17,520 square miles) of territory in Iraq and Syria and 7,323 km of territory elsewhere, for a total of 52,700 square kilometres (20,300 sq mi). This represents a substantial decline from the group's territorial peak in late 2014, when it controlled between 100,000 and 110,000 square kilometres (39,000 and 42,000 sq mi) of territory in total. IS territory has declined substantially in almost every country since 2014, a result of the group's unpopularity and the military action taken against it. By late March 2019, IS territory in Syria was reduced to only the besieged 4,000 km (1,550 sq mi) Syrian Desert pocket. The enclave was surrounded by Syrian government forces and its allies. The Syrian military conducted combing operations and airstrikes against the pocket, but with limited success. IS propaganda claims a peak territorial extent of 282,485 km.

The Eastern Syria campaign of September–December 2017 was a large-scale military operation of the Syrian Army (SAA) and its allies against the Islamic State of Iraq and the Levant (ISIL) during the Syrian Civil War. Its goal was to clear the city of Deir ez-Zor of any remaining ISIL forces, capture ISIL's de facto capital of Mayadin, as well as seize the border town of Abu Kamal, which became one of ISIL's final urban strongholds by the latter stages of the campaign.

The campaign was concurrent with the 2017 Western Iraq campaign, the Raqqa campaign conducted by the Syrian Democratic Forces (SDF) against ISIL's former capital city of Raqqa, as well as with the SDF's offensive in Deir ez-Zor province along the eastern banks of the Euphrates River.