American-led intervention in the Syrian Civil War in the context of "Deir ez-Zor campaign (2017–2019)"

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).

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.