Baghdad was the capital city of Iraq.
While stationed in Iraq, Sergeant Decker's Army Ranger team, which included Eric Carter and Ben Grimes, deployed on a mission in Baghdad's Sadr City district to protect intelligence agents at a meeting with Tariq Al-Hashem's militia. (Rules of Engagement)
Sometime following Day 6, the President of the United States was planning a trip to Baghdad. The White House had called it a "big step", and a helicopter was waiting for the President to board it. (The Rookie · "Extraction")