The Battle of Mosul was a major battle initiated by the Iraqi Government forces with allied militias, the Kurdistan Regional Government, and international forces to retake the city of Mosul from the Islamic State (ISIL), which had seized the city years prior in June 2014. It was the largest conventional land battle since the capture of Baghdad in 2003, it was also the world's single largest military operation overall since the 2003 invasion of Iraq and was considered the toughest urban battle since World War II. The operation, which was called Operation "We Are Coming, Nineveh", began on 16 October 2016, with forces besieging ISIL-controlled areas in the Nineveh Governorate surrounding Mosul, and continued with Iraqi troops and Peshmerga fighters engaging ISIL on three fronts outside Mosul, going from village to village in the surrounding area in the largest deployment of Iraqi troops since the 2003 invasion of Iraq.

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