The Anbar campaign consisted of fighting between the United States military, together with Iraqi security forces, and Sunni insurgents in the western Iraqi governorate of Al Anbar. The Iraq War lasted from 2003 to 2011, but the majority of the fighting and counterinsurgency campaign in Anbar took place between April 2004 and September 2007. Although the fighting initially featured heavy urban warfare primarily between insurgents and U.S. Marines, insurgents in later years focused on ambushing the American and Iraqi security forces with improvised explosive devices (IEDs), large scale attacks on combat outposts, and car bombings. Almost 9,000 Iraqis and 1,335 Americans were killed in the campaign, many in the Euphrates River Valley and the Sunni Triangle around the cities of Fallujah and Ramadi.
Al Anbar, the only Sunni-dominated province in Iraq, saw little fighting in the initial invasion. Following the fall of Baghdad it was occupied by the U.S. Army's 82nd Airborne Division. Violence began on 28 April 2003 when 17 Iraqis were killed in Fallujah by U.S. soldiers during an anti-American demonstration. In early 2004 the U.S. Army relinquished command of the governorate to the Marines. By April 2004 the governorate was in full-scale revolt. Savage fighting occurred in both Fallujah and Ramadi by the end of 2004, including the Second Battle of Fallujah. Violence escalated throughout 2005 and 2006 as the two sides struggled to secure the Western Euphrates River Valley. During this time, Al Qaeda in Iraq (AQI) became the governorate's main Sunni insurgent group and turned the provincial capital of Ramadi into its stronghold. The Marine Corps issued an intelligence report in late 2006 declaring that the governorate would be lost without a significant additional commitment of troops.
In August 2006, several tribes located in Ramadi and led by Sheikh Abdul Sattar Abu Risha began to form what would eventually become the Anbar Awakening, which later led to the tribes revolting against AQI. The Anbar Awakening helped turn the tide against the insurgents through 2007. American and Iraqi tribal forces regained control of Ramadi in early 2007, as well as other cities such as Hīt, Haditha, and Rutbah. More hard fighting still followed throughout the Summer of 2007 however, particularly in the rural western River Valley, due largely to its proximity to the Syrian border and the vast network of natural entry points for foreign fighters to enter Iraq, via Syria. In June 2007 the U.S. turned a majority of its attention to eastern Anbar Governorate and secured the cities of Fallujah and Al-Karmah.
The fighting was mostly over by September 2007, although US forces maintained a stabilizing and advisory role through December 2011. Celebrating the victory, President George W. Bush flew to Anbar in September 2007 to congratulate Sheikh Sattar and other leading tribal figures. AQI assassinated Sattar days later. In September 2008, political control was transferred to Iraq. Military control was transferred in June 2009, following the withdrawal of American combat forces from the cities. The Marines were replaced by the US Army in January 2010. The Army withdrew its combat units by August 2010, leaving only advisory and support units. The last American forces left the governorate on 7 December 2011.
Al Anbar is Iraq's largest and westernmost governorate. It comprises 32 percent of the country's total land mass, nearly 53,208 square miles (137,810 km2), almost exactly the size of North Carolina in the United States and slightly larger than Greece. Geographically, it is isolated from most of Iraq, but is easy to access from Saudi Arabia, Jordan, and Syria. The Euphrates River, Lake Habbaniyah, and the artificially created Lake Qadisiyah are its most significant geographical features. Outside of the Euphrates area the terrain is overwhelmingly desert, comprising the eastern part of the Syrian Desert. Temperatures range from highs of 115 °F (46 °C) in July and August to below 50 °F (10 °C) from November to March. The governorate lacks significant natural resources and many inhabitants benefited from the Ba'athist government's patronage system, funded by oil revenues from elsewhere in the country.
The Coalition Provisional Authority (CPA) estimated that about 1.2 million Iraqis lived in Anbar in 2003, more than two-thirds of them in Fallujah and Ramadi. With a population 95 percent Sunni, many from the Dulaimi Tribe, Anbar is Iraq's only governorate without a significant Shia or Kurdish population. 95 percent of the population lives within 5 miles (8.0 km) of the Euphrates. At the time of the invasion, Fallujah was known as a religious enclave hostile towards outsiders, while Ramadi, the provincial capital, was more secular. Outside the cities, the ancient tribal system run by Sheikhs held considerable influence.
Conditions in Anbar particularly favored an insurgency. The province was overwhelmingly Sunni, the minority religious group that lost its power and influence in post-Saddam Hussein Iraq. Saddam was also very popular in the province more than anywhere else in the country. Many did not fight during the invasion (allowing them to claim that they had not been defeated) and "still wanted to slug it out", according to journalist Tom Ricks. Military service was compulsory in Saddam's Iraq and the Amiriyah area contained a sizeable portion of Iraq's arms industry. Immediately after Saddam fell, insurgents and others looted many of the 96 known munitions sites, as well as local armories and weapons stockpiles. These weapons were used to arm the insurgents in Anbar and elsewhere. While only a small minority of Sunnis were initially insurgents, many either supported or tolerated them. Sympathetic Ba'athists and former Saddam officials in Syrian exile provided money, sanctuary, and foreign fighters to insurgent groups. Future al-Qaeda in Iraq leader Abu Musab al-Zarqawi spent part of 2002 in central Iraq, including Anbar Governorate, preparing for resistance. Within several months of the invasion, the governorate had become a sanctuary for anti-occupation fighters.
Anbar experienced relatively little fighting during the initial invasion of Iraq, as the main US offensive was directed through the Shia areas of southeastern Iraq, from Kuwait to Baghdad. An infantry division had been earmarked in 2002 to secure Anbar during the invasion. However, the Pentagon decided to treat the province with an "economy of force" in early 2003. The first Coalition forces to enter Al Anbar were American and Australian special forces, who seized vital targets such as Al Asad Airbase and Haditha Dam and prevented the launch of Scud missiles at Israel. While there was generally little combat, the most significant engagement occurred when elements of the American 3rd Battalion 75th Ranger Regiment seized Haditha Dam on 31 March 2003. Surrounded by a larger Iraqi force, the Rangers held the dam until relieved after eight days. During the siege, they destroyed twenty-nine Iraqi tanks and killed an estimated 300 to 400 Iraqi soldiers. Three Rangers were awarded the Silver Star for the action. In addition, four other Rangers were killed when their checkpoint near Haditha was attacked by a suicide bomber.
At the end of the invasion, the pro-Saddam forces in Anbar–the Ba'ath Party, the Republican Guard, the Fedayeen Saddam, and the Iraqi Intelligence Service—remained intact. Saddam hid in Ramadi and Hīt in early April. Other pro-Saddam forces were able to relocate from Anbar to Syria with money and weapons, where they set up headquarters. The nucleus of the insurgency in its first few months was formed from the pro-Saddam forces in Anbar and Syria. In contrast to the looting throughout Baghdad and other parts of the country, Ba'athist headquarters and homes of high-ranking Sunni leaders were relatively untouched. The head of Iraqi ground forces in the province, General Mohammed Jarawi, formally surrendered to elements of the 3rd Infantry Division at Ramadi on 15 April 2003.