On December 11, 2016, just before my time as Secretary of Defense would end, I stepped off a C-130 transport plane onto a cold and dusty patch of northern Iraq that had been on my mind for more than a year: an Iraqi military airfield called Qayyarah West. Q-West, as it was known to the American military, was a talisman of progress on one of the defining issues of my time as secretary, the fight to defeat ISIS. A year before, General Joe Dunford and I had briefed the President on a plan to energize the counter-ISIS fight. We had laid out a series of military tasks, in Iraq and Syria, that would lead us to the liberation of ISIS’ strongholds in Mosul, Iraq, and Raqqa, Syria. Q-West was a fulcrum of that plan. Ejecting ISIS and turning the airstrip into a logistics hub was essential to seizing Mosul, just 40 miles to the north.
Carter, Ashton B. "A Lasting Defeat: The Campaign to Destroy ISIS." October 2017.