Sadr City, a sprawling slum in northeastern Baghdad, is home to over 2 million Iraqis and has the largest Shi’a population in Baghdad. Sadr City was built in 1959 and unofficially named for Ayatollah Mohammad Sadeq al-Sadr, the highly-revered Shi’a cleric who was assassinated by the Saddam Hussein’s regime in 1999. Sadr City presents one of the biggest security challenges for U.S. forces in Baghdad.
The southern provinces of Maysan, Dhi Qar, Muthanna, and Basra are populated almost entirely by Shi’a Arabs, in the major cities of Amarah, Nasariyah, and Basra, as well as in the rural marshlands. Of these provinces, Basra is the primary economic hub.
Iran has been actively involved in supporting Shi'a militias and encouraging sectarian violence in Iraq since the invasion of 2003.