In January 2014, three years after the American withdrawal from Iraq, Fallujah was captured by the Islamic State (IS) and suffered a major population decline.

In the spring of 1920, the British, who had gained control of Iraq after the collapse of the Ottoman Empire, sent Lieut.-Colonel Gerard Leachman, a renowned explorer and a senior colonial officer, to meet with local leader Shaykh Dhari, perhaps to forgive a loan given to the sheikh.

[8] Exactly what happened depends on the source, but according to the Arab version, Gerard Leachman was betrayed by the sheikh who had his two sons shoot him in the legs, then behead him by the sword.

Under Saddam Hussein, who ruled Iraq from 1979 to 2003, Fallujah came to be an important area of support for the regime, along with the rest of the region labeled by the US military as the "Sunni Triangle".

[9] Fallujah was heavily industrialised during the Saddam era, with the construction of several large factories, including one closed down by United Nations Special Commission (UNSCOM) in the 1990s that may have been used to create chemical weapons.

A new highway system as a part of Saddam's infrastructure initiatives circumvented Fallujah and gradually caused the city to decline in national importance by the time of the Iraq War.

On 14 February 1991, a Royal Air Force (RAF) fighter jet fired two laser-guided missiles which were aimed at the bridge but malfunctioned and instead struck Fallujah's largest marketplace (which was situated in a residential area), killing between 50 and 150 non-combatants and wounding many more.

After news of the mistake became public, an RAF spokesman, Group Captain David Henderson, issued a statement noting that the missile had malfunctioned but admitted that the Royal Air Force had made an error.

Coalition warplanes subsequently launched another attack on the bridge, with one missile hitting its target while two others fell into the river and a fourth struck another marketplace in Fallujah, due to its laser guidance system once again malfunctioning.

Iraqi Army units stationed in the area abandoned their positions and disappeared into the local population, leaving unsecured military equipment behind.

On the evening of 28 April 2003, a crowd of about two hundred people defied a curfew imposed by the Americans and gathered outside a secondary school used as a military HQ to demand its reopening.

On 31 March 2004, Iraqi insurgents in Fallujah ambushed a convoy containing four American private military contractors from Blackwater USA, who were conducting delivery for food caterers ESS.

[14] The four, armed contractors, Scott Helvenston, Jerry (Jerko) Zovko, Wesley Batalona, and Michael Teague, were dragged from their cars, beaten, and set on fire.

[17] Photographs of the event were released to news agencies worldwide, causing outrage in the United States, and prompting the announcement of a campaign to reestablish American control over the city.

[21][22] On 17 May 2011, AFP reported that twenty-one bodies, in black body-bags marked with letters and numbers in Latin script had been recovered from a mass grave in al-Maadhidi cemetery in the center of the city.

[22] Residents were allowed to return to the city in mid-December 2004 after undergoing biometric identification, provided they wear their ID cards all the time.

[24] According to Mike Marqusee of Iraq Occupation Focus writing in the Guardian, "Fallujah's compensation commissioner has reported that 36,000 of the city's 50,000 homes were destroyed, along with 60 schools and 65 mosques and shrines".

estimates by the Iraqi Ministry of Interior and Coalition Forces put the city's population at over 350,000, possibly closing in on half a million.

In the aftermath of the offensive, relative calm was restored to Fallujah although almost-daily attacks against coalition forces resumed in 2005 as the population slowly trickled back into the city.

In January 2014, a variety of sources reported that the city was controlled by al-Qaeda and/or the Islamic State of Iraq and the Levant (ISIS; sometimes called ISIL).

[4][30][31] On a broadcast of National Public Radio's All Things Considered, Middle East analyst Kirk Sowell stated that while ISIS was occupying parts of the city, most of the ground lost was to the tribal militias who are opposed to both the Iraqi government and al-Qaeda.

[34] On the same day, the Iraqi Army shelled the city of Fallujah with mortars to try to wrest back control from Sunni Muslim militants and tribesmen, killing at least eight people, tribal leaders and officials said.

[38] Speaking on condition of anonymity at the end of May 2014, an Anbar-based Iraqi government security officer told Human Rights Watch that ISIS controlled several neighborhoods of southeast Fallujah as well as several northern and southern satellite communities, while local militias loyal to the Anbar Military Council controlled the central and northern neighborhoods of the city; however, Human Rights Watch stated that they could not confirm these claims.

[40][41] After beginning a campaign to liberate Anbar Governorate from ISIL in July 2015, in February 2016, the Iraqi army and its allies started to encircle the city in the Siege of Fallujah.

On 26 June, the Iraqi army reported that it had fully liberated the city, while fighting was ongoing in some pockets northwest of Fallujah which remained under ISIL control.

Truckers and travelers from Saudi Arabia, Jordan and southern Syria all merge onto this highway prior to entering the Eastern Al Anbar province.

[48] The authors cautioned that while "the results seem to qualitatively support the existence of serious mutation-related health effects in Fallujah, owing to the structural problems associated with surveys of this kind, care should be exercised in interpreting the findings quantitatively".