After the withdrawal of U.S. troops from Syria caused turmoil in the region, Statista's Niall McCarthy notes that some units formerly stationed in Syria have moved to stay in Iraq.
The country had formerly been the base of more than 5,000 U.S. troops, as our graphic shows.
Other Middle Eastern countries host many more U.S. troops.
The largest U.S. base in the Middle East is in Qatar. The country hosts around 13,000 U.S. troops, according to numbers compiled by Axios. Located southwest of Doha, Al Udeid Air Base has proven crucial in the fight against ISIS. Qatar invested $1 billion in constructing the base and it's also home to the the U.S. Combined Air Operations Center, responsible for coordinating U.S. and allied air power across the Middle East, particularly in airspace over Iraq, Syria and Afghanistan.
The above infographic also highlights just how important Qatar, along with Kuwait, is to the U.S. presence in the Middle East.
Both countries hosts an estimated 13,000 U.S. troops.
Neighboring Bahrain is also vital to American interests in the region, home to the Naval Support Activity Bahrain, the U.S. Fifth Fleet and a substantial military presence at Isa Air Base. 7,000 troops are based there.